A waste liquid recycling treatment device for l-alanine

Abstract

The application relates to a waste liquid recycling treatment equipment applied to L-alanine and to the technical field of L-alanine waste liquid treatment; the equipment comprises a crystallization tank, a steam jacket is arranged outside the crystallization tank, the crystallization tank is arranged in a tapered cylindrical structure which is wide at the top and narrow at the bottom, a liquid inlet spraying assembly for feeding waste liquid into the crystallization tank is arranged at the upper end of the inside of the crystallization tank, a crystal slurry discharge pipe is connected to the lower end of the crystallization tank, and an annular discharge valve is arranged at the crystal slurry discharge pipe; a driving shaft is further arranged along the axis of the crystallization tank, and a stirring and scraping assembly for descaling the waste liquid and the inner wall of the crystallization tank is arranged on the driving shaft; through the cooperative action of the variable-diameter variable-pitch scraping auger and the reverse-spiral extension auger, in combination with partition steam heating and rotary liquid film dispersion, the wall scaling rate and the bottom blocking risk in the L-alanine waste liquid crystallization process are significantly reduced, fine crystal recovery and mother liquor recycling are realized, and the crystallization yield and product purity are improved.

Description

Technical Field

[0001] This invention relates to the technical field of wastewater treatment of L-alanine, and particularly to a wastewater reuse treatment device for L-alanine. Background Technology

[0002] L-Alanine is an important natural amino acid widely used in pharmaceuticals, food, chemicals, and daily chemicals. During the fermentation or enzymatic production of L-alanine, a large amount of waste liquid containing residual L-alanine, byproducts, and inorganic salts is generated. To reduce production costs, minimize pollutant emissions, and improve resource utilization, this waste liquid is typically recycled. The crystallization step is a key process for separating and purifying L-alanine.

[0003] For example, Chinese patent CN121446157A discloses a low-energy evaporator crystallizer with anti-scaling properties. The low-energy evaporator crystallizer uses a single drive motor, which drives a scraping component located in the evaporation cylinder to perform dynamic scraping and solution stirring through a rotating shaft. One end of the rotating shaft drives a spiral separation component in the gas-liquid separation tank to rotate at high speed through a first transmission mechanism and a linkage shaft, thereby enhancing gas-liquid separation. The other end drives a discharge component in the crystal slurry discharge pipe to rotate through a second transmission mechanism, thereby achieving anti-blocking discharge and negative pressure slag discharge.

[0004] However, the aforementioned existing technologies still have some shortcomings in practical use: In horizontal crystallizers, it is difficult to achieve an absolutely uniform temperature and concentration field in the horizontal direction. When the material is stationary in the tank, the bottom and walls of the tank are in contact with the jacket, resulting in lower temperatures and making it easier for scale to form. Meanwhile, the top of the tank above the liquid surface does not participate in crystallization and has less scale formation.

[0005] When the scraping assembly rotates along a fixed path, there is almost no effective contact resistance between the scraper and the vessel wall when facing the tank top area where scaling is weak. The cleaning mechanism is in an idle state. Over time, not only will it be unable to perform targeted cleaning based on the crystallization situation in different locations, but the power consumption of the drive motor will also be wasted. The scraper will experience unnecessary wear due to the lack of resistance, increasing maintenance costs. Summary of the Invention

[0006] To address the problems of existing technologies where the scraper has almost no effective contact resistance with the tank wall in areas with weak scaling, resulting in the cleaning mechanism running idle and unable to target specific crystallization conditions, this invention provides a waste liquid reuse treatment device for L-alanine. The device includes a crystallization tank with a steam jacket installed on its outer side. The crystallization tank is a conical cylindrical structure, wider at the top and narrower at the bottom. An inlet spray assembly for waste liquid entry into the crystallization tank is located at the upper end, and a crystal slurry outlet pipe is connected to the lower end, with an annular outlet valve installed at the outlet pipe. A drive shaft is also installed along the tank's axis inside, and a stirring and scraping assembly for descaling the waste liquid and the inner wall of the crystallization tank is mounted on the drive shaft. The stirring and scraping assembly includes lifting spiral blades and scraping spiral blades, both mounted on the drive shaft. The scraping spiral blades are sleeved outside the lifting spiral blades, and their diameter gradually decreases from top to bottom.

[0007] Preferably, the lifting spiral blades and the scraping spiral blades have opposite spiral directions.

[0008] Preferably, a discharge spiral blade is rotatably installed inside the crystal slurry discharge pipe, and the discharge spiral blade is connected to the drive shaft via a one-way clutch.

[0009] Preferably, the liquid inlet spray assembly includes an annular spray pipe, which is connected to multiple nozzles. The spray pipe is connected to a waste liquid inlet pipe, and a dispersing platform is provided below the spray pipe. The spray direction of the nozzles is all towards the top edge of the side wall of the dispersing platform. The dispersing platform is a hollow annular plate structure that is narrow at the top and wide at the bottom.

[0010] Preferably, the dispersion table is rotatably disposed inside the crystallization tank and connected to the drive shaft.

[0011] Preferably, a gas-liquid separator is installed above the crystallization tank, and the outlet of the gas-liquid separator is connected to the upper end of the crystallization tank and located above the side of the dispersion table.

[0012] Preferably, the steam jacket is divided into three independent heating zones—upper, middle, and lower—along the height of the crystallizer. Each heating zone is equipped with an independent steam circulation device, as well as an air inlet and an air outlet.

[0013] Preferably, a purge pipe is also installed at the upper end of the crystallization tank. The purge pipe is tangentially arranged at the connection between the purge pipe and the crystallization tank, and the purge pipe is connected to an external inert gas source.

[0014] Preferably, a separation tank connected to the crystal slurry discharge pipe is installed at the bottom of the crystallization tank. A synchronous shaft is rotatably installed inside the separation tank along its axis. The synchronous shaft is connected to the output shaft of the discharge spiral blades. A support column is slidably sleeved at the bottom of the synchronous shaft. A ring-shaped filter screen with a high center and low perimeter is sleeved on the support column. A return pipe is configured at the bottom of the separation tank and is connected to the interior of the separation tank. An output pipe connected to the interior of the separation tank is installed on one side. Vertically distributed discharge scrapers are connected to the synchronous shaft. The discharge scrapers are slidably connected to the synchronous shaft, and the bottom of the discharge scrapers is in contact with the filter screen.

[0015] Preferably, multiple fixing plates are equidistantly arranged on the side wall of the separator along the axis of the bottom of the filter screen. The fixing plates are connected to the filter screen by springs. A stop post is installed at the bottom of the synchronous shaft below the support column via an extension plate. A wave-shaped groove is opened at the bottom of the support column, and the stop post slides against the groove.

[0016] In summary, this application includes at least one of the following beneficial technical effects: I. This invention utilizes scraping spiral blades and lifting spiral blades with opposite spiral directions to push the bottom material upwards. The two blades form an internal material circulation in the axial direction, pushing upwards and scraping downwards. This effectively prevents high-viscosity slurry from depositing and clogging the slurry outlet pipe at the bottom of the cone, and continuously scrapes away the scale layer attached to the inner wall, ensuring long-term stability of heat transfer efficiency and avoiding material deterioration caused by local overheating.

[0017] Second, this invention uses a liquid inlet spray assembly in conjunction with a rotating dispersion table to form a continuous thin liquid film from the waste liquid, thereby increasing the evaporation area and reducing foam. The steam jacket is divided into three independent heating zones: upper, middle, and lower. The temperature can be adjusted separately to meet the heating requirements of different concentration zones, achieving a balance between rapid concentration and gentle crystallization. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0020] Figure 2 This is a cross-sectional schematic diagram of the steam jacket of the present invention.

[0021] Figure 3 This is the present invention. Figure 2 A schematic diagram of the structure at point A in the middle.

[0022] Figure 4 This is a schematic diagram of the internal structure of the crystallization tank of the present invention.

[0023] Figure 5 This is a schematic diagram of the structure of the stirring and scraping assembly of the present invention.

[0024] Figure 6 This is a schematic diagram of the internal structure of the separation tank of the present invention.

[0025] Figure 7 This is a schematic diagram of the installation of the filter screen of the present invention.

[0026] Figure 8 This is the present invention. Figure 7 A schematic diagram of the structure at point B.

[0027] In the diagram, 1 is the crystallizer; 2 is the steam jacket; 20 is the steam inlet; 21 is the steam outlet; 3 is the liquid inlet spray assembly; 30 is the spray pipe; 31 is the nozzle; 32 is the waste liquid inlet pipe; 33 is the dispersion platform; 40 is the crystal slurry outlet pipe; 41 is the annular outlet valve; 50 is the drive shaft; 51 is the stirring and scraping assembly; 510 is the lifting spiral blade; 511 is the scraping spiral blade; 60 is the discharge spiral blade; 61 is the one-way clutch; 7 is the gas-liquid separator; 8 is the purge pipe; 9 is the separation tank; 90 is the synchronous shaft; 91 is the support column; 92 is the filter screen; 93 is the return pipe; 94 is the output pipe; 95 is the unloading scraper; 96 is the fixed plate; 97 is the abutment column; and 98 is the chute. Detailed Implementation

[0028] The following combination Figures 1-8 The embodiments of the present invention will be described in detail below.

[0029] This application discloses a waste liquid recycling and treatment device for L-alanine. The invention is mainly applied in the crystallization process of L-alanine waste liquid, which can avoid the problems of scaling on the inner wall of the crystallization tank and material deposition and blockage at the bottom of the cone. Specifically, the scraping spiral blades and the lifting spiral blades are arranged in opposite spirals to achieve wall cleaning and bottom pushing. At the same time, the pitch of the scraping spiral blades gradually decreases from top to bottom to enhance the cleaning frequency of the bottom area of ​​the cone. Furthermore, the invention can also solve the problem of L-alanine entrainment in the steam during the evaporation process, which leads to a decrease in yield and scaling on the inner wall of the tank top. Fine crystals are recovered by a gas-liquid separator and sent back to the rotating dispersion table to re-participate in crystallization.

[0030] Reference Figure 1 , Figure 4 and Figure 5As shown, a waste liquid recycling and treatment device for L-alanine is disclosed. This invention is mainly applied to the crystallization stage of the L-alanine waste liquid recycling process. The pre-treated waste liquid is crystallized to separate the L-alanine inside for further recycling and reuse. It includes a crystallization tank 1, with a steam jacket 2 installed on the outside of the crystallization tank 1. The crystallization tank 1 is designed as a conical cylindrical structure that is wider at the top and narrower at the bottom. The conical cylindrical structure, together with the steam jacket 2, creates a temperature gradient and natural circulation of the waste liquid inside the crystallization tank 1. The upper part of the tank is equipped with a liquid inlet spray assembly 3 for the waste liquid to enter the crystallization tank 1, and the lower part is connected to a crystal slurry outlet pipe 40 to evenly spray the L-alanine waste liquid onto the inner wall of the crystallization tank 1. The steam jacket 2 provides a stable heat source to promote the evaporation of water, and the concentration of the waste liquid gradually increases and L-alanine crystals precipitate.

[0031] Inside the crystallizer 1, a drive shaft 50 is also installed along its axis. The drive shaft 50 is equipped with a stirring and scraping assembly 51 for descaling the waste liquid and the inner wall of the crystallizer 1.

[0032] The stirring and scraping assembly 51 includes a lifting spiral blade 510 and a scraping spiral blade 511. Both the lifting spiral blade 510 and the scraping spiral blade 511 are mounted on the drive shaft 50. The scraping spiral blade 511 is sleeved on the outside of the lifting spiral blade 510, and the diameter of the scraping spiral blade 511 gradually decreases from top to bottom. The drive shaft 50 is driven to rotate by an external motor. The lifting spiral blade 510 rotates with the drive shaft 50 and generates an upward pushing force on the concentrated material at the bottom of the crystallizer 1, preventing high-viscosity materials or crystals from depositing and clogging the crystal slurry outlet pipe 40 at the conical bottom.

[0033] Because the diameter of the scraping spiral blade 511 gradually decreases from top to bottom, it can closely fit the conical inner wall of the crystallization tank 1. During the rotation, it continuously scrapes off the L-alanine scale layer attached to the inner wall, avoiding the thickening of the scale layer which leads to a decrease in the heat transfer coefficient or causes local overheating and deterioration. The scraped crystals are carried by the waste liquid to re-participate in crystallization or settle and are discharged from the crystal slurry discharge pipe 40.

[0034] The spiral distance of the scraper auger blades 511 gradually decreases from top to bottom. Since there is more crystal deposition in the lower part, the denser scraper auger blades 511 can increase the cleaning frequency. In the wider upper part of the crystallization tank 1, the amount of crystal deposition is relatively small, and the larger spiral distance is sufficient to maintain basic wall scraping and material conveying.

[0035] Reference Figure 4 and Figure 5The diagram shows the specific structure of the lifting spiral blade 510 and the scraping spiral blade 511. Specifically, the lifting spiral blade 510 and the scraping spiral blade 511 have opposite spiral directions. When the drive shaft 50 rotates in the forward direction, the lifting spiral blade 510 pushes the material upward while the scraping spiral blade 511 scrapes the material downward. Their working areas complement each other. The lifting spiral blade 510 enhances axial mixing and bottom discharge, while the scraping spiral blade 511 ensures the cleanliness of the wall surface. At the same time, the relative motion generated by the reverse spiral further promotes the internal circulation of waste liquid and the uniform distribution of crystals, avoiding dead zones or excessive accumulation of material between the spiral blade 510 and the scraping spiral blade 511.

[0036] Reference Figure 4 The diagram shows a structure that facilitates the discharge of slurry from the inside of the discharge pipe 40. Specifically, a discharge spiral blade 60 is rotatably installed inside the discharge pipe 40. The discharge spiral blade 60 is connected to the drive shaft 50 via a one-way clutch 61. When the drive shaft 50 rotates forward, the one-way clutch 61 is disengaged, and the discharge spiral blade 60 does not rotate with the drive shaft 50. During the crystallization process, the discharge spiral blade 60 does not work, thereby avoiding unnecessary axial disturbance or mechanical breakage of the L-alanine crystals growing in the crystallization tank 1, and maintaining the stability of the crystallization system and the integrity of crystal growth.

[0037] When the drive shaft 50 reverses, the one-way clutch 61 engages, the discharge spiral blade 60 rotates in the opposite direction with the drive shaft 50, and forces the crystals remaining in the crystal slurry discharge pipe 40 to be transported outward, thereby effectively preventing the crystal slurry discharge pipe 40 from becoming blocked when the machine is stopped or at low flow.

[0038] Reference Figure 4 The diagram shows a structure that promotes the uniform feeding of L-alanine waste liquid into the crystallization tank 1. Specifically, the liquid inlet spray assembly 3 includes an annular spray pipe 30, which is connected to multiple nozzles 31. The spray pipe 30 is connected to the waste liquid inlet pipe 32, and a dispersion platform 33 is provided below the spray pipe 30. The spray direction of the nozzles 31 is all towards the top edge of the side wall of the dispersion platform 33.

[0039] The dispersing platform 33 is a hollow annular plate structure that is narrow at the top and wide at the bottom. The waste liquid feed pipe 32 sends L-alanine waste liquid into the annular spray pipe 30. The waste liquid is sprayed through multiple nozzles 31 to the upper end of the side of the dispersing platform 33. The structure of the dispersing platform 33, which is narrow at the top and wide at the bottom, allows the waste liquid to spread evenly in all directions along its slope and form a continuous liquid film. The liquid film then drips naturally from the edge of the dispersing platform 33 or flows to the inner wall of the crystallization tank 1, increasing the evaporation area of ​​the waste liquid and preventing local oversaturation caused by droplet splashing.

[0040] After the waste liquid forms a continuous liquid film, it gradually accumulates at the bottom of the crystallization tank 1, which reduces the foam generated by direct spraying and avoids the problem of a large amount of foam occupying the evaporation interface, hindering water evaporation and reducing heat transfer efficiency.

[0041] Reference Figure 4 The diagram shows a schematic of the structure controlling the rotation of the dispersion platform 33. Specifically, the dispersion platform 33 is rotatably installed inside the crystallization tank 1 and connected to the drive shaft 50. The drive shaft 50 drives the dispersion platform 33 to rotate synchronously. During the rotation, the dispersion platform 33 generates centrifugal force, which causes the L-alanine waste liquid sprayed from the nozzle 31 to the upper side of the dispersion platform 33 to be quickly thrown outward along the inclined surface of the dispersion platform 33, forming a thinner liquid film. The combined action of centrifugal force and gravity makes the waste liquid evenly cover the upper part of the inner wall of the crystallization tank 1, avoiding local liquid accumulation or dry spots that may occur during static dispersion.

[0042] Meanwhile, the hollow annular plate structure of the dispersing platform 33 will not interfere with the operation of the lifting spiral blade 510 and the scraping spiral blade 511 below when it rotates.

[0043] Reference Figure 4 The diagram shows a structure for further gas-liquid separation of the steam generated during the evaporation and crystallization process. Specifically, a gas-liquid separator 7 is configured above the crystallization tank 1. The gas-liquid separator 7 is preferably a cyclone separator. The outlet of the gas-liquid separator 7 is connected to the upper end of the crystallization tank 1 and is located above the side of the dispersion platform 33.

[0044] The water vapor generated by evaporation in crystallizer 1 carries a small amount of L-alanine droplets or tiny crystal powder and rises into gas-liquid separator 7. Gas-liquid separator 7 uses centrifugal force to efficiently separate the droplets and solid particles in the gas. The clean steam after separation is discharged from the top of the separator. The separated and recovered liquid or fine crystals containing L-alanine are returned to the top of crystallizer 1 through the outlet and drip onto the upper side of the rotating dispersion table 33. After mixing with the fresh waste liquid and the condensate returned by the steam trap, they re-participate in the crystallization process, reducing the loss of L-alanine with steam entrainment, improving the total product yield, and avoiding the accumulation of fine crystals on the inner wall of the top of the tank to form hard scale that is difficult to remove. This enables the entire evaporation crystallization system to achieve efficient separation and resource reuse of the gas, liquid and solid three phases.

[0045] Reference Figure 2 , Figure 3 and Figure 4The diagram shows a structural schematic for improving the working efficiency of the steam jacket 2. Specifically, the steam jacket 2 is divided into three independent heating zones—upper, middle, and lower—along the height of the crystallizer 1. Each heating zone is equipped with an independent steam circulation device, a steam inlet 20, and a steam outlet 21. Both the steam inlet 20 and the steam outlet 21 are connected to an external steam circulation device via pipes. The external steam circulation device is a conventional device well-known to those skilled in the art. Each independent heating zone can adjust the steam flow rate and pressure according to the material temperature requirements at different heights within the crystallizer 1. The upper heating zone corresponds to the low-concentration waste liquid area after spraying and dispersion, providing a higher evaporation temperature for rapid concentration. The middle heating zone corresponds to the crystal growth area, maintaining relatively stable medium-temperature conditions to promote uniform crystal growth. The lower heating zone corresponds to the high-concentration slurry and crystal sedimentation area, using a lower temperature or micro-heating to prevent overheating and decomposition and maintain crystal fluidity.

[0046] Reference Figure 4 The diagram shows a structural schematic for cleaning the dispersing platform 33 and the scraper spiral blades 511. Specifically, a purge pipe 8 is installed at the upper end of the crystallization tank 1. The purge pipe 8 is tangentially arranged at the connection point with the crystallization tank 1. The purge pipe 8 is connected to an external inert gas source. The gas enters the upper end of the tank along the tangential direction of the inner wall of the crystallization tank 1 through the tangentially arranged purge pipe 8, forming a spiral downward circulating airflow inside the tank. The inert gas circulation continuously purges the upper space that is difficult for the dispersing platform 33 and the scraper spiral blades 511 to reach, preventing fine L-alanine dust from accumulating and forming a crust on the inner wall of the tank top or on the liquid inlet spray assembly 3.

[0047] Reference Figure 6 , Figure 7 and Figure 8 The diagram shows a structural schematic for screening crystals. Specifically, a separation tank 9 connected to the crystal slurry discharge pipe 40 is installed at the bottom of the crystallizer 1. A synchronous shaft 90 is rotatably installed inside the separation tank 9 along its axis. The synchronous shaft 90 is connected to the output shaft of the discharge spiral blade 60. A support column 91 is slidably fitted onto the bottom of the synchronous shaft 90 via a guide key. An annular filter screen 92, which is higher in the center and lower around the edges, is fitted onto the support column 91. A return pipe 93 is configured at the bottom of the separation tank 9 and is connected to the interior of the separation tank 9. The material from the bottom of the crystallizer 1, delivered by the crystal slurry discharge pipe 40, directly enters the separation tank 9 and undergoes solid-liquid separation on the annular filter screen 92. The filter screen 92 intercepts L-alanine crystals. The mother liquor or fine particles pass through the filter screen 92 and are discharged through the return pipe 93 at the bottom, returning to the crystallizer 1 for reuse, thus realizing online recovery of the mother liquor.

[0048] An output pipe 94 communicating with the interior of the separator 9 is installed on one side. Vertically distributed discharge scrapers 95 are connected to the synchronous shaft 90. The discharge scrapers 95 are slidably connected to the synchronous shaft 90, and the bottom of the discharge scrapers 95 contacts the filter screen 92. The synchronous shaft 90 rotates synchronously with the drive shaft 50 of the discharge spiral blades 60, driving the vertically distributed discharge scrapers 95 to continuously scrape the surface of the filter screen 92. The discharge scrapers 95 push the discharge product out of the output pipe 94 as the target product, while the residual microcrystals in the mother liquor are returned through the return pipe 93 to continue growing. This ensures the uniformity of the particle size of the target product and realizes the resource reuse of the mother liquor and microcrystals.

[0049] Reference Figure 6 , Figure 7 and Figure 8 The diagram shows the structure for controlling the vibration of the filter screen 92. Specifically, multiple fixing plates 96 are equidistantly arranged on the side wall of the separator 9 at the bottom of the filter screen 92 along its axis. The fixing plates 96 are connected to the filter screen 92 by springs. A stop post 97 is installed at the bottom of the synchronous shaft 90 below the support column 91 via an extension plate. A wave-shaped groove 98 is opened at the bottom of the support column 91. The stop post 97 slides against the groove 98. The discharge scraper 95 is rotatably connected to the support column 91. When the synchronous shaft 90 rotates, the stop post 97 moves along the wave-shaped groove 98, forcing the support column 91 to drive the filter screen 92 to vibrate up and down. Under the action of vibration and gravity, the crystals on the filter screen 92 automatically slide to the lower parts of the surrounding area, avoiding the accumulation of crystals in the middle and clogging the filter holes. The discharge scraper 95 has more sufficient contact with the crystals at the edge of the filter screen 92. The discharge scraper 95 pushes the crystals out of the output pipe 94 as the target product.

[0050] The unloading scraper 95 is rotatably connected to the support column 91, allowing the unloading scraper 95 to rotate or swing independently relative to the support column 91. When the filter screen 92 vibrates up and down, the unloading scraper 95 can adaptively adjust the contact angle with the surface of the filter screen 92, further reducing the residue of crystals on the filter screen 92.

[0051] During operation: First, the L-alanine waste liquid is sprayed onto the rotating dispersing platform 33 through the spray pipe 30 and nozzle 31. Under the action of centrifugal force, the dispersing platform 33 throws the waste liquid into a thin liquid film and flows down the inner wall of the crystallization tank 1, increasing the evaporation area. During the crystallization process, the discharge spiral blade 60 is connected to the drive shaft 50 through a one-way clutch 61. When the drive shaft 50 rotates forward, the discharge spiral blade 60 does not work to avoid disturbing crystal growth; when the drive shaft 50 rotates in reverse, the discharge spiral blade 60 forcibly pushes the material in the crystal slurry discharge pipe 40.

[0052] In the second step, the drive shaft 50 drives the lifting spiral blades 510 to push the bottom material upward to prevent the bottom of the cone from being blocked by deposits; at the same time, the scraping spiral blades 511 rotate closely against the inner wall of the cone to scrape off the attached scale layer.

[0053] Step 3: The water vapor generated by evaporation carries a small amount of droplets and fine crystals into the cyclone gas-liquid separator 7. The separated clean steam is discharged, and the recovered liquid containing L-alanine is returned to the dispersion stage 33 to participate in crystallization again.

[0054] Step 4: The bottom of the crystallizer 1 is connected to the separation tank 9. The material undergoes solid-liquid separation on the annular filter screen 92. The crystals intercepted by the filter screen 92 are pushed to the output pipe 94 by the rotating discharge scraper 95. The mother liquor and microcrystals return to the crystallizer 1 for reuse after passing through the filter screen 92. The filter screen 92 vibrates up and down to prevent clogging.

[0055] Step 5: Inert gas enters the upper part of the tank from the tangential purge pipe 8, forming a spiral downward circulation to purge areas that are difficult to reach, such as the dispersion platform 33 and the liquid inlet spray assembly 3, to prevent dust and dirt accumulation.

[0056] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0057] It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be regarded as exemplary and non-limiting in all respects.

[0058] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A waste liquid recycling treatment device for L-alanine, comprising a crystallization tank (1), wherein a steam jacket (2) is installed on the outside of the crystallization tank (1), characterized in that: The crystallization tank (1) is set as a conical cylindrical structure with a wider top and a narrower bottom. The upper part of the tank is equipped with a liquid inlet spray assembly (3) for waste liquid to enter the crystallization tank (1), and the lower part is connected to a crystal slurry outlet pipe (40). An annular outlet valve (41) is installed at the crystal slurry outlet pipe (40). Inside the crystallizer (1), a drive shaft (50) is also installed along its axis. The drive shaft (50) is equipped with a stirring and scraping assembly (51) for descaling the waste liquid and the inner wall of the crystallizer (1). The mixing and scraping assembly (51) includes a lifting spiral blade (510) and a scraping spiral blade (511). Both the lifting spiral blade (510) and the scraping spiral blade (511) are mounted on the drive shaft (50). The scraping spiral blade (511) is sleeved on the outside of the lifting spiral blade (510), and the diameter of the scraping spiral blade (511) gradually decreases from top to bottom.

2. The wastewater reuse treatment equipment for L-alanine according to claim 1, characterized in that: The lifting spiral blade (510) has the opposite spiral direction to the scraping spiral blade (511).

3. The wastewater reuse treatment equipment for L-alanine according to claim 1, characterized in that: A discharge spiral blade (60) is rotatably installed inside the crystal slurry discharge pipe (40), and the discharge spiral blade (60) is connected to the drive shaft (50) through a one-way clutch (61).

4. The wastewater reuse treatment equipment for L-alanine according to claim 1, characterized in that: The liquid inlet spray assembly (3) includes an annular spray pipe (30), the spray pipe (30) is connected to multiple nozzles (31), the spray pipe (30) is connected to the waste liquid inlet pipe (32), a dispersing platform (33) is provided below the spray pipe (30), and the spraying direction of the nozzles (31) is all towards the top edge of the side wall of the dispersing platform (33). The dispersing platform (33) is a hollow annular plate structure that is narrow at the top and wide at the bottom.

5. The wastewater reuse treatment equipment for L-alanine according to claim 4, characterized in that: The dispersion table (33) is rotatably mounted inside the crystallization tank (1) and connected to the drive shaft (50).

6. The wastewater reuse treatment equipment for L-alanine according to claim 4, characterized in that: A gas-liquid separator (7) is installed above the crystallization tank (1). The outlet of the gas-liquid separator (7) is connected to the upper end of the crystallization tank (1) and is located above the side of the dispersion platform (33).

7. The wastewater reuse treatment equipment for L-alanine according to claim 1, characterized in that: The steam jacket (2) is divided into three independent heating zones along the height direction of the crystallizer (1): upper, middle and lower. Each heating zone is equipped with an independent steam circulation device as well as an air inlet and an air outlet.

8. The wastewater reuse treatment equipment for L-alanine according to claim 1, characterized in that: A purge pipe (8) is also installed at the upper end of the crystallizer (1). The purge pipe (8) is tangentially arranged at the connection between the crystallizer (1) and the purge pipe (8), and the purge pipe (8) is connected to an external inert gas source.

9. The wastewater reuse treatment equipment for L-alanine according to claim 1, characterized in that: The bottom of the crystallizing tank (1) is equipped with a separation tank (9) that is connected to the crystal slurry discharge pipe (40). A synchronous shaft (90) is installed inside the separation tank (9) along its axis. The synchronous shaft (90) is connected to the output shaft of the discharge spiral blade (60). A support column (91) is slidably sleeved at the bottom of the synchronous shaft (90). A ring-shaped filter screen (92) with a high center and low periphery is sleeved on the support column (91). A return pipe (93) is configured at the bottom of the separation tank (9). The return pipe (93) is connected to the interior of the separation tank (9). The separator (9) has an output pipe (94) connected to its interior on one side. A vertically distributed discharge scraper (95) is connected to the synchronous shaft (90). The discharge scraper (95) is slidably connected to the synchronous shaft (90), and the bottom of the discharge scraper (95) is in contact with the filter screen (92).

10. The wastewater reuse treatment equipment for L-alanine according to claim 9, characterized in that: On the side wall of the separator (9), multiple fixing plates (96) are equidistantly arranged at the bottom of the filter screen (92) along its axis. The fixing plates (96) and the filter screen (92) are connected by springs. The bottom of the synchronous shaft (90) is equipped with a stop post (97) through an extension plate below the support column (91). The bottom of the support column (91) is provided with a wave-shaped groove (98). The stop post (97) slides against the groove (98).

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