Crystallization reactor for extracting phosphorus from anaerobic digestion liquid

Abstract

The crystallization reactor comprises a reaction kettle, an input pipeline, an output pipeline and an automatic control system, wherein the input pipeline and the output pipeline are matched with the reaction kettle; the interior of the reaction kettle sequentially comprises a pretreatment bin for removing suspended matters, a coarse precipitation bin for injecting a precipitator for reaction, a fine precipitation bin for centrifuging a mixed solution flowing downwards from the coarse precipitation bin and a discharge hopper for discharging wastewater flowing downwards from the fine precipitation bin into the anaerobic system from top to bottom; the reaction kettle is designed in different bins, different processes are carried out on each layer, additional separation or feeding equipment is not needed, and the use space and funds are saved.

Description

Technical Field

[0001] The invention belongs to the field of environmental protection and resource recycling, and in particular relates to a crystallization reactor for extracting phosphorus from anaerobic digestion liquid. Background Art

[0002] Anaerobic digestion is a common strategy for waste activated sludge (WAS) treatment, with the advantages of considerable resource recovery (e.g., volatile fatty acids (VFAs)) and reduced environmental risks (e.g., toxic and hazardous substances). However, phosphorus accumulated in WAS is released into the digestate in large quantities during anaerobic digestion, with phosphate concentrations as high as 75-300 mg / L.

[0003] In view of the above facts, phosphorus recovery from digestion liquid is quite applicable and promising. Its main recovery technologies include:

[0004] Electrodialysis: A method of removing phosphorus and recovering phosphorus by using an electric field to make wastewater pass through a selective membrane. This method has high investment and operation and management costs. In addition, membrane fouling caused by the process of recovering nutrients from wastewater is a challenge faced by all electrodialysis technologies. The accumulation of fouling layers increases the resistance of the cell (current decreases), reduces mobility and ion selectivity, and ultimately changes the properties of the membrane due to irreversible fouling.

[0005] Adsorption method: It mainly uses adsorbents with large specific surface area and affinity to adsorb and remove phosphorus from sewage or sludge. However, this method has strict requirements for adsorbents. In actual operation, there are problems such as low removal rate, large amount of adsorbent, slow adsorption rate, and immature process.

[0006] Ion exchange method: a method that uses the groups in the ion exchange resin to undergo a replacement reaction with the phosphate radicals in the solution. It also has problems such as high cost and low resin exchange capacity.

[0007] Crystallization method: It mainly involves adding chemical phosphorus removal agents to precipitate phosphate substances in the sludge concentrate in the form of crystals to form insoluble phosphates such as struvite (magnesium salt), hydroxyapatite (calcium salt), aluminum phosphate (aluminum salt), and blue iron ore (iron salt) for recovery. It has the advantages of wide research and mature application, high utilization value of recovered products, and high recovery efficiency.

[0008] When using the crystallization method for phosphorus extraction, a specific reactor is often required to ensure internal sealing, anaerobic, graded filtration and wastewater discharge. Therefore, how to design a reactor that can improve phosphorus removal efficiency and recover valuable products is a problem that needs to be solved at present. Summary of the invention

[0009] In view of the above defects, the present invention provides a crystallization reactor for extracting phosphorus from anaerobic digestion liquid, comprising a reactor and input and output pipes and an automatic control system adapted to the reactor, wherein the interior of the reactor comprises, from top to bottom, a pretreatment bin for removing suspended matter, a coarse sedimentation bin for injecting a precipitant for reaction, a fine sedimentation bin for centrifuging a mixed liquid downstream of the coarse sedimentation bin, and a discharge hopper for discharging wastewater downstream of the fine sedimentation bin into an anaerobic system;

[0010] The input pipeline includes a feed pipe connected to the interior of the pretreatment bin and a feed pipe connected to the coarse precipitation bin;

[0011] The automatic control system includes a solenoid valve for controlling the inlet and outlet of each pipeline and a PLC controller for controlling each electrical component;

[0012] A cleaning mechanism for cleaning each chamber is also installed inside the reactor.

[0013] Furthermore, the coarse sedimentation bin comprises a cylinder body I adapted to the kettle cover, a floating plate is hinged on the top of the inner wall of the cylinder body I, the floating plate penetrates the cylinder body I through an insertion rod, and is driven by a forward and reverse motor installed on the outer surface of the cylinder body I;

[0014] The bottom of the cylinder body I is sealed by a bottom plate I, and an opening in the middle of the bottom plate I is connected to the fine sedimentation bin through an installed solenoid valve I.

[0015] Furthermore, the outer ring of the floating plate is fitted with the inner wall of the cylinder body 1 through a fixed brush ring;

[0016] The bidirectional rotation angles of the forward and reverse motors are both between 15° and 30°.

[0017] Furthermore, the fine sedimentation bin comprises a cylinder II and a bottom plate II, and a filter screen located outside the solenoid valve I is installed inside the cylinder II for filtering the fine sediment;

[0018] The inner wall of the cylinder II is also inlaid with a number of equally spaced electric heating rods for heating, and the electric heating rods are located on the inner wall of the cylinder II to form a continuous protrusion, and each electric heating rod is connected through a built-in wire outside the cylinder II;

[0019] A discharge port is provided in the middle of the bottom plate II, and the discharge port is movably connected to a sealing plate through an elastic member, and the bottom of the sealing plate is connected to a fixed plate through symmetrically distributed linkage rods, and electric push rods with anti-corrosion functions are provided on the left and right sides of the upper surface of the fixed plate, and the telescopic end of the electric push rod is connected to the bottom surface of the bottom plate II;

[0020] A rotating hole is also provided in the middle of the sealing plate, and a rotating rod passes through the rotating hole. The rotating rod stirs the inside of the filter screen through a push plate fixed on the outer surface, and the rotating rod is driven by a driving device installed outside the reactor.

[0021] Furthermore, the filter screen includes an outer filter screen cylinder and an inner filter screen cylinder arranged from outside to inside, the inner filter screen cylinder is seated inside the outer filter screen cylinder, and the pore size value of the outer filter screen cylinder is greater than the pore size value of the inner filter screen cylinder.

[0022] Furthermore, the driving device includes a servo motor installed on the outer wall of the reactor through a mounting frame and a transmission box used to pass through the reactor. The transmission box is a hollow structure. A transmission groove is opened on the left side of the transmission box. A bearing is inlaid on the right side of the transmission box. The inner ring of the bearing is fixed with a transmission rod that passes through the transmission box and is used to connect with the rotating rod. A sprocket I is fixedly sleeved at one end of the transmission rod located inside the transmission box. A sprocket II is installed at the output end of the servo motor. Sprocket I and sprocket II are connected by a chain transmission that passes through the transmission groove.

[0023] Furthermore, the bottom plate I and the bottom plate II are both concave.

[0024] Furthermore, the cleaning mechanism includes a plurality of annularly distributed high-pressure nozzles embedded in the top of the outer wall of the pretreatment bin, the coarse sedimentation bin, the fine sedimentation bin and the discharge bucket. Each row of high-pressure nozzles is connected through a rubber hose, and the rubber hose is connected to an external water pump through an inlet valve.

[0025] Furthermore, the diameter of the coarse sedimentation bin is greater than the diameter of the fine sedimentation bin, and the coarse sedimentation bin is hinged to the rotating shaft seat at the fine sedimentation bin through a rotating shaft to realize opening and closing movements after rotation.

[0026] Furthermore, the input pipe includes a raw material pipe installed at the kettle cover, a precipitant feeding pipe installed at the coarse precipitation bin, a pH additive pipe installed at the fine precipitation bin, and an inert gas pipe for replacing the air inside the reactor;

[0027] The output pipe is a discharge pipe connected to the anaerobic system at the bottom of the discharge hopper and is equipped with a solenoid valve II;

[0028] A flow meter is installed at each input pipe to control the input flow.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The reactor is designed with compartments, and each layer performs different processes. No additional separation or feeding equipment is required, saving space and money:

[0031] The pre-treatment chamber is roughly screened through the built-in screen;

[0032] The crude sedimentation tank is used to add precipitants (such as magnesium salts and ammonia) to promote the formation and precipitation of compounds such as magnesium ammonium phosphate (struvite), while controlling the pH value to optimize the precipitation reaction;

[0033] The fine sedimentation tank separates the formed sediment through the filter screen through the internal centrifugal action to complete the storage function for subsequent passivation and use;

[0034] The extracted liquid can then be re-entered into the anaerobic digestion system or otherwise treated to maximize resource recovery and waste disposal;

[0035] 2. The swing of the floating plate can isolate the impurities in the raw material before adding the precipitant. During the swinging process, the raw material flows down from the gaps on both sides;

[0036] 3. The function of classification and refinement screening is realized by using two filters with different aperture values, and the broken crystals and large crystals are classified and collected to facilitate subsequent classification processing;

[0037] 4. Ensure the best crystallization efficiency inside the reactor by automatically controlling pH value, anaerobic environment and temperature;

[0038] 5. It can separate and recover high-value phosphorus-containing products such as magnesium salts, iron salts, and calcium salts. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a front view of the present invention.

[0040] Figure 2 It is an exploded view of the coarse sedimentation bin in the present invention.

[0041] Figure 3 It is an exploded view of the fine sedimentation bin in the present invention.

[0042] Figure 4 It is a structural schematic diagram of the transmission box in the present invention.

[0043] Figure 5 It is a schematic diagram of the sealing plate in the raised state in the present invention.

[0044] Figure 6 It is a top view of the bottom plate II of the present invention.

[0045] Figure 7 This is a schematic diagram of the coarse sedimentation bin and the fine sedimentation bin in Example 2 being hinged via a rotating shaft and a rotating shaft seat.

[0046] In the figure: 1, reactor; 2, pretreatment chamber; 3, coarse sedimentation chamber; 301, cylinder I; 302, floating plate; 303, plug rod; 304, brush loop; 305, forward and reverse motor; 306, bottom plate I; 307, solenoid valve I; 4, fine sedimentation chamber; 401, cylinder II; 402, outer filter cylinder; 403, inner filter cylinder; 404, electric heating rod; 405, built-in wire; 406, bottom plate II; 407, driving device; 4071, transmission box; 4072, chain; 4073, transmission rod; 4074, servo motor; 408, rotating hole; 409, sealing plate; 410, fixing plate; 411, connecting rod; 412, elastic member; 413, electric push rod; 414, rotating rod; 415, push plate; 5, discharge bucket; 6, cleaning mechanism; 71, rotating shaft; 72, rotating shaft seat. DETAILED DESCRIPTION

[0047] In order to facilitate the understanding of the present invention, the device of the present invention will be described more fully below with reference to the relevant drawings. Embodiments of the device are given in the drawings. However, the device can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0048] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "set" should be understood in a broad sense, for example, they can be fixedly connected or set, or detachably connected or set, or integrally connected or set. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] Example 1

[0050] like Figure 1-6 As shown, this embodiment provides a crystallization reactor for extracting phosphorus from anaerobic digestion liquid, including a reactor 1 and input and output pipes and an automatic control system adapted to the reactor 1.

[0051] The interior of the reactor 1 includes, from top to bottom, a pretreatment chamber 2 for removing suspended matter, a coarse sedimentation chamber 3 for injecting a precipitant for reaction, a fine sedimentation chamber 4 for centrifuging the mixed liquid downstream of the coarse sedimentation chamber 3, and a discharge hopper 5 for discharging the wastewater downstream of the fine sedimentation chamber 4 into the anaerobic system;

[0052] In detail, the inner bottom wall of the pretreatment bin 2 is a screen, which is used to preliminarily screen the input raw liquid, and then flow into the coarse sedimentation bin 3.

[0053] In detail, the coarse sedimentation bin 3 includes a cylinder body 1301 covered and sealed by a kettle cover, a floating plate 302 is hinged on the top of the inner wall of the cylinder body 1301, and the outer ring of the floating plate 302 is fitted with the inner wall of the cylinder body 1301 through a fixed brush ring 304, and its function is to fill the gap between the outer ring of the floating plate 302 and the cylinder body 1301, and the floating plate 302 penetrates the inner wall of the cylinder body 1301 through the insertion rod 303, and is then driven by a forward and reverse motor 305 installed on the outer surface of the cylinder body 1301 (that is, the output end of the forward and reverse motor 305 is connected to the penetration end of the insertion rod 303). It should be noted that the bidirectional rotation angle of the forward and reverse motor 305 is between 15° and 30°, and a reducer is added to reduce the speed. The forward and reverse motor 305 is controlled by a PLC controller to perform forward and reverse or reverse. In this embodiment, a rotation angle of 15° is used to realize the function of the insertion rod 303 driving the floating plate 302 to swing, so that the floating impurities are always at the top of the liquid surface to be skimmed off;

[0054] In this process, chemical additives such as metal salts are added to the interior of the cylinder I301 through the precipitant feeding pipe to promote the precipitation of phosphorus;

[0055] The bottom of the cylinder I301 is sealed by the bottom plate I306, and the opening in the middle of the bottom plate I306 is connected to the fine sedimentation bin 4 through the installed solenoid valve I307. The solenoid valve I307 is controlled to open and close by a PLC controller. The solenoid valve I307 and the forward and reverse motor 305 should be adapted to each other, that is, when the forward and reverse motor 305 is working, the solenoid valve I307 is always in a closed stage. In this embodiment, the forward and reverse motor 305 is set to operate for 30 minutes, and then the solenoid valve I307 is opened to complete the internal raw liquid flow to the fine sedimentation bin 4 for fine screening.

[0056] In detail, the fine sedimentation bin 4 includes a cylinder II401 connected to the coarse sedimentation bin 3, and a bottom plate II406 sealing the cylinder II401. Since the solenoid valve I307 is located at the top of the cylinder II401, a filter screen located outside the solenoid valve I307 needs to be installed inside the cylinder II401 to filter the fine sediment;

[0057] The filter screen includes an outer filter screen cylinder 402 and an inner filter screen cylinder 403 arranged from outside to inside, and the inner filter screen cylinder 403 is located inside the outer filter screen cylinder 402, and the aperture value of the outer filter screen cylinder 402 is larger than the aperture value of the inner filter screen cylinder 403, which is used to achieve graded filtration and realize the classification and storage function of small particle crystallization and normal particle crystallization;

[0058] The inner wall of the cylinder II401 is also inlaid with a number of equally spaced electric heating rods 404 for heating. The electric heating rods 404 are located on the inner wall of the cylinder II401 to form a continuous protrusion, that is, the inner wall of the cylinder II401 is reserved with a protrusion storage cavity during molding, which is used to place the electric heating rods 404 installed later. Each electric heating rod 404 is connected through a built-in wire 405 outside the cylinder II401 and is uniformly controlled by a power switch. Its function is to promote the dissolution and precipitation of phosphorus by heating to a medium temperature of 35-40°C or a high temperature of 50-55°C.

[0059] A discharge port is provided in the middle of the bottom plate II406, and the discharge port is movably connected to a sealing plate 409 through an elastic member 412. The elastic member 412 is specifically a plurality of spring telescopic rods arranged in a circular array or a tension spring made of corrosion-resistant material, which can meet the rebound and reset function of the sealing plate 409. The bottom of the sealing plate 409 is connected to a fixed plate 410 through a symmetrically distributed linkage rod 411, and the left and right sides of the upper surface of the fixed plate 410 are provided with an anti-corrosion electric push rod 413, and the telescopic end of the electric push rod 413 is connected to the bottom surface of the bottom plate II406. The electric push rod 413 is also controlled by a PLC controller, and the sealed discharge port is opened by pushing the sealing plate 409 upward after being raised, so that the wastewater is discharged to the internal treatment of the discharge bucket 5, which is used to simulate the function of the switch gate, and at the same time can ensure the normal rotation of the subsequent rotating rod 414;

[0060] A rotating hole 408 is also provided in the middle of the sealing plate 409, and a rotating rod 414 is passed through the rotating hole 408. A corrosion-resistant rubber ring is provided between the rotating rod 414 and the rotating hole 408. The rotating rod 414 stirs the inside of the filter screen through a push plate 415 fixed on the outer surface. Since the electric heating rod 404 forms a convexity, when stirring, the internal water source contacts the convex surface to form fluctuations, and a certain water flow tumbling effect can be achieved during the clockwise stirring process, thereby improving the mixing efficiency.

[0061] The rotating rod 414 is driven by a driving device 407 installed on the outside of the reactor 1, wherein the driving device 407 includes a servo motor 4074 installed on the outer wall of the reactor 1 through a mounting frame and a transmission box 4071 for penetrating the reactor 1. The servo motor 4074 is controlled by a PLC controller. The transmission box 4071 is a hollow structure. A transmission groove is provided on the left side of the transmission box 4071. A bearing is embedded on the right side of the transmission box 4071. A transmission rod 4073 penetrating the transmission box 4071 and connected to the rotating rod 414 is fixed on the inner ring of the bearing. The two are respectively connected by The cross slot and the cross protrusion are inserted and connected, and a sprocket I is fixedly sleeved at one end of the transmission rod 4073 located inside the transmission box 4071, and a sprocket II is installed at the output end of the servo motor 4074. The sprocket I and the sprocket II are connected for transmission via a chain 4072 that runs through the transmission groove, that is, the servo motor 4074 drives the sprocket II to rotate, and then the chain 4072 drives the sprocket I to rotate, thereby driving the transmission rod 4073. Similarly, when the PLC controller controls the servo motor 4074 to operate, the electric push rod 413 is not powered on, and vice versa.

[0062] The reactor 1 is also provided with a cleaning mechanism 6 for cleaning each chamber. The cleaning mechanism 6 includes a plurality of annularly distributed high-pressure nozzles embedded in the top of the outer wall of the pretreatment chamber 2, the coarse sedimentation chamber 3, the fine sedimentation chamber 4 and the discharge hopper 5. Each row of high-pressure nozzles is connected by a rubber hose, and the rubber hose is connected to an external water pump through a water inlet valve.

[0063] In addition, the bottom plate I306 and the bottom plate II406 are both concave, which is convenient for material cutting;

[0064] It should be noted that before the reactor 1 is operated, the inert gas pipeline needs to first inject inert gas into the reactor 1 so that the internal air is discharged from the raw material pipe to ensure the anaerobic environment inside the reactor 1.

[0065] The input pipe includes a raw material pipe installed at the kettle cover, a precipitant feeding pipe installed at the coarse precipitation bin 3, a pH additive pipe installed at the fine precipitation bin 4, and an inert gas pipe for replacing the air inside the reactor 1, so as to ensure that the crystallization work inside the reactor 1 can proceed smoothly;

[0066] The output pipe is a discharge pipe connected to the anaerobic system at the bottom of the discharge hopper 5, and is equipped with a solenoid valve II, which is controlled by PLC to perform the last step of the discharge operation;

[0067] A flow meter is installed at each input pipe to control the input flow.

[0068] Example 2

[0069] like Figure 7As shown, the difference from Example 1 is that the coarse sedimentation bin 3 is hinged to the shaft seat 72 at the fine sedimentation bin 4 through the shaft 71, and the diameter of the coarse sedimentation bin 3 is greater than the diameter of the fine sedimentation bin 4. Its function is to realize the opening and closing movement after rotation, which is convenient for taking the crystals. However, it should be noted that a sealing gasket needs to be added at the open end, and after the rotation seal, a sealing ring or sealing tape needs to be added to the outer ring of the connection between the two.

[0070] It should be noted that the structure described in the present invention can be implemented in a variety of different forms and is not limited to the described embodiments. Any equivalent transformations made by ordinary technicians in this field using the contents of the present invention description and drawings, or directly or indirectly applied to other related technical fields, such as the loading and unloading of other items, are included in the protection scope of the present invention.

Claims

1. A crystallization reactor for extracting phosphorus from anaerobic digestion liquid, comprising a reactor and input and output pipes and an automatic control system adapted to the reactor, characterized in that: The interior of the reactor includes, from top to bottom, a pretreatment tank for removing suspended matter, a coarse sedimentation tank for injecting a precipitant for reaction, a fine sedimentation tank for centrifuging the mixed liquid downstream of the coarse sedimentation tank, and a discharge hopper for discharging the wastewater downstream of the fine sedimentation tank into the anaerobic system; The input pipeline includes a feed pipe connected to the interior of the pretreatment bin and a feed pipe connected to the coarse precipitation bin; The automatic control system includes a solenoid valve for controlling the inlet and outlet of each pipeline and a PLC controller for controlling each electrical component; A cleaning mechanism for cleaning each chamber is also installed inside the reactor.

2. A crystallization reactor for extracting phosphorus from anaerobic digestion liquid as claimed in claim 1, characterized in that: The coarse sedimentation bin comprises a cylinder body I adapted to the kettle cover, a floating plate is hinged on the top of the inner wall of the cylinder body I, the floating plate penetrates the cylinder body I through an insertion rod, and is driven by a forward and reverse motor installed on the outer surface of the cylinder body I; The bottom of the cylinder body I is sealed by a bottom plate I, and an opening in the middle of the bottom plate I is connected to the fine sedimentation bin through an installed solenoid valve I.

3. A crystallization reactor for extracting phosphorus from anaerobic digestion liquid as claimed in claim 2, characterized in that: The outer ring of the floating plate is fitted with the inner wall of the cylinder body 1 through a fixed brush ring; The bidirectional rotation angles of the forward and reverse motors are both between 15° and 30°.

4. A crystallization reactor for extracting phosphorus from anaerobic digestion liquid as claimed in claim 2, characterized in that: The fine sedimentation bin comprises a cylinder II and a bottom plate II, and a filter screen located outside the solenoid valve I is installed inside the cylinder II for filtering the fine sediment; The inner wall of the cylinder II is also inlaid with a number of equally spaced electric heating rods for heating, and the electric heating rods are located on the inner wall of the cylinder II to form a continuous protrusion, and each electric heating rod is connected through a built-in wire outside the cylinder II; A discharge port is provided in the middle of the bottom plate II, and the discharge port is movably connected to a sealing plate through an elastic member, and the bottom of the sealing plate is connected to a fixed plate through symmetrically distributed linkage rods, and electric push rods with anti-corrosion functions are provided on the left and right sides of the upper surface of the fixed plate, and the telescopic end of the electric push rod is connected to the bottom surface of the bottom plate II; A rotating hole is also provided in the middle of the sealing plate, and a rotating rod passes through the rotating hole. The rotating rod stirs the inside of the filter screen through a push plate fixed on the outer surface, and the rotating rod is driven by a driving device installed outside the reactor.

5. A crystallization reactor for extracting phosphorus from anaerobic digestion liquid as claimed in claim 4, characterized in that: The filter screen comprises an outer filter screen cylinder and an inner filter screen cylinder which are arranged from outside to inside. The inner filter screen cylinder is located inside the outer filter screen cylinder, and the pore size value of the outer filter screen cylinder is greater than the pore size value of the inner filter screen cylinder.

6. A crystallization reactor for extracting phosphorus from anaerobic digestion liquid as claimed in claim 4, characterized in that: The driving device includes a servo motor installed on the outer wall of the reactor through a mounting frame and a transmission box used to penetrate the reactor. The transmission box is a hollow structure. A transmission groove is opened on the left side of the transmission box. A bearing is inlaid on the right side of the transmission box. A transmission rod that penetrates the transmission box and is connected to the rotating rod is fixed on the inner ring of the bearing. A sprocket I is fixedly sleeved at one end of the transmission rod located inside the transmission box. A sprocket II is installed at the output end of the servo motor. The sprocket I and the sprocket II are connected by a chain transmission that penetrates the transmission groove.

7. A crystallization reactor for extracting phosphorus from anaerobic digestion liquid as claimed in claim 4, characterized in that: The bottom plate I and the bottom plate II are both concave.

8. A crystallization reactor for extracting phosphorus from anaerobic digestion liquid as claimed in claim 1, characterized in that: The cleaning mechanism includes a plurality of annularly distributed high-pressure nozzles embedded in the top of the outer wall of the pretreatment bin, the coarse sedimentation bin, the fine sedimentation bin and the discharge bucket. Each row of high-pressure nozzles is connected through a rubber hose, and the rubber hose is connected to an external water pump through a water inlet valve.

9. A crystallization reactor for extracting phosphorus from anaerobic digestion liquid as claimed in claim 1, characterized in that: The diameter of the coarse sedimentation bin is greater than the diameter of the fine sedimentation bin. The coarse sedimentation bin is hinged to the rotating shaft seat at the fine sedimentation bin through a rotating shaft to realize opening and closing movements after rotation.

10. A crystallization reactor for extracting phosphorus from anaerobic digestion liquid as claimed in claim 1, characterized in that: The input pipe includes a raw material pipe installed at the kettle cover, a precipitant feeding pipe installed at the coarse precipitation bin, a pH additive pipe installed at the fine precipitation bin, and an inert gas pipe for replacing the air inside the reactor; The output pipe is a discharge pipe connected to the anaerobic system at the bottom of the discharge hopper and is equipped with a solenoid valve II; A flow meter is installed at each input pipe to control the input flow.

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