Filtering system with reaction aging crystallization function and filtering method

Abstract

The invention belongs to the technical field of reaction crystallization type solid-liquid separation, and particularly relates to a filtering system with reaction aging crystallization functions and a filtering method. The filtering system comprises a reaction kettle and a centrifugal filter disc, wherein a reserved channel for materials to move upwards and filter cakes to move downwards is formed between the disc edge of the centrifugal filter disc and the inner wall of the reaction kettle; the upper disc surface of the centrifugal filter disc is provided with a filter surface, the kettle cavity of the reaction kettle is communicated with a liquid accumulation cavity positioned in the centrifugal filter disc through the filter surface, the liquid accumulation cavity is discharged to mother liquid collection equipment through a transition channel and a mother liquid outlet in sequence, and a slag outlet communicated with crystal collection equipment is formed in the bottom of the reaction kettle; the device further comprises a first material pipeline, a second material pipeline, a compressed air pipeline and a bridging branch. According to the invention, the smoothness of the filtering medium channel and the reliability and convenience of the unloading operation can be effectively ensured, and the effects of compact pipeline layout and simple and reasonable structure are achieved.

Description

Technical Field

[0001] The present application belongs to the technical field of reaction crystallization solid-liquid separation, and specifically relates to a filtration system and a filtration method with reaction aging crystallization functions. Background Art

[0002] The filtration device is a general device used for solid-liquid two-phase separation or concentration, with large quantity and wide application. It is generally composed of filter media such as filter screen, filter cloth or filter element. Under the action of air pressure, vacuum force, mechanical force, etc., the material forms a pressure difference on both sides of the filter medium, allowing the liquid to pass through the channel of the filter medium, while the solid is retained on the surface of the filter medium, thereby achieving the purpose of solid-liquid separation or concentration.

[0003] In the engineering applications of chemical, pharmaceutical and other industries, there are often some reaction crystallization conditions. The materials need to react in the device to generate crystals. Generally, they also need to go through the aging stage to allow the crystals to continue in the mother liquor for a period of time so that the reaction is sufficient, the crystals grow and grow, and the crystals are complete. However, due to the existence of the filter medium, the crystals will be formed in the holes of the filter medium during the reaction, crystallization and aging stages, resulting in blockage and failure of the filter medium channel. To solve such problems, the reaction, crystallization and aging are generally carried out in the reactor. After the crystals are completed, they are transferred to the filter device for solid-liquid separation, washing, drying and other operations. The transportation process is required and the production process is complicated. There are also some multifunctional filtering devices. Through the flipping action, the filter medium is first flipped to the top so that the feed liquid cannot contact the filter medium, and the reaction, crystallization and aging processes are carried out; then the equipment is flipped back to its original position, and the filter medium returns to the normal bottom for filtering, washing and other operations. However, this type of equipment can only be used in occasions with low equipment parameters, small volume and small loading capacity. It is not suitable for industrial production and engineering fields with large diameters and large loading capacities. It is mostly used in small-scale material situations such as laboratories. Industrial production urgently needs a filtration system with high technical parameters, easy operation, reasonable pipeline layout and multiple functions such as reaction, crystallization, aging, filtration, washing and unloading to meet the needs of large-scale production. Summary of the invention

[0004] The purpose of this application is to overcome the deficiencies of the above-mentioned prior art and to provide a filtration system with reaction aging and crystallization functions, which can not only effectively ensure the smooth flow of the filter medium channel and the reliability and convenience of the unloading operation, but also has the effect of compact pipeline layout and simple and reasonable structure.

[0005] To achieve the above objectives, this application adopts the following technical solutions:

[0006] A filtration system with reaction, aging and crystallization functions includes a reactor installed on a bracket, and is characterized in that: it also includes a centrifugal filter disc located in the reactor and capable of rotating and lifting, and a reserved channel for materials to go up and filter cakes to go down is provided between the disc edge of the centrifugal filter disc and the inner wall of the reactor; the upper disc surface of the centrifugal filter disc has a filtering surface, the reactor cavity is connected to the liquid accumulation cavity located in the centrifugal filter disc through the filtering surface, the liquid accumulation cavity is discharged to the mother liquid collection device through the transition channel and the mother liquid outlet in sequence, and a slag outlet connected to the crystallization collection device is arranged at the bottom of the reactor;

[0007] The first material source is connected to the first material inlet of the stirring kettle through a first material pipeline with a first switch valve, the second material source is connected to the second material inlet of the stirring kettle through a second material pipeline with a second switch valve, and the compressed air source is connected to the air inlet through a compressed air pipeline with a third switch valve; an air outlet is also arranged at the stirring kettle, and the air outlet is connected to the gas collecting device via a seventh switch valve; a fifth switch valve is arranged between the mother liquor outlet and the mother liquor collecting device, and a bridging branch with a fourth switch valve is bridged between the inlet of the fifth switch valve and the outlet of the compressed air source.

[0008] Preferably, it also includes a sixth switch valve for controlling the on and off of the slag outlet, and the power of the sixth switch valve comes from a compressed air source.

[0009] Preferably, the filter surface is in the shape of a cone that gradually descends from the axis of the centrifugal filter disk to the disk edge.

[0010] Preferably, the centrifugal filter disc includes a liquid accumulation disc and a circular orifice plate covering the opening of the liquid accumulation disc, the area enclosed by the lower plate surface of the circular orifice plate and the liquid accumulation disc cavity forms the liquid accumulation cavity; the upper plate surface of the circular orifice plate is in the shape of a cone that gradually descends from the axis to the edge of the disc, the filter screen is fixed on the upper plate surface in a covering manner, and the upper surface of the filter screen constitutes the filtering surface.

[0011] Preferably, the centrifugal filter disc is installed on the lid of the reactor via a rotating shaft, and the rotation is achieved by a power motor; a hollow cavity is coaxially arranged inside the rotating shaft, and the hollow cavity constitutes a transition channel for the circulation of mother liquor and back-blowing air; the bottom of the hollow cavity extends to the lowest point of the liquid accumulation cavity through a liquid guide tube, and the top of the hollow cavity is connected to external equipment through a rotating joint.

[0012] Preferably, an annular tube is coaxially installed near the edge of the liquid accumulation tray, and the wall of the annular tube is connected to the wall of the liquid guiding tube through a radially extending connecting tube; the spray hole is arranged on the side of the annular tube facing the filter surface.

[0013] Preferably, a partition bar is provided on the upper surface of the circular orifice plate for equally dividing the upper surface, and in the circumferential direction of the circular orifice plate, two adjacent groups of partition bars form a fixed area for fixing the fan-shaped sub-segments; each sub-segment is assembled together on the plate surface of the circular orifice plate to form a filter.

[0014] Preferably, the power motor is mounted on a fixed frame; it also includes a piston cylinder, the two ends of which are respectively fixed to the fixed frame and the reactor cover, so that the centrifugal filter disc is driven to produce a lifting action through the stroke action of the piston cylinder; it also includes a guide column for guiding the travel direction of the centrifugal filter disc.

[0015] Preferably, a guide paddle is arranged at the bottom of the centrifugal filter disc for guiding the filter cake toward the direction of the slag outlet at the axis of the bottom of the kettle.

[0016] Preferably, a filtering method, which uses the filtering system with reaction aging and crystallization function, is characterized by comprising the following steps:

[0017] S1. Feeding and reaction steps:

[0018] The first valve and the second valve are opened, the first material enters the reactor from the first feed port, and the second material enters the reactor from the second feed port, then all valves are reset and closed, the two materials are mixed to form a mixed liquid and start to react;

[0019] S2. Aging and crystallization steps:

[0020] As the materials in the kettle react, crystals gradually precipitate and grow, and at this time the centrifugal filter disc remains in a high position without contacting the mixed liquid;

[0021] S3. Filter pressing and dehydration step:

[0022] At this time, the centrifugal filter disc at a high position is controlled to move downward, contact the mixture, and generate a rotating motion at the same time. The mixed liquid is stirred and moves upward to the filter surface through the reserved channel; then, the third valve and the fifth valve are opened, and compressed air enters the reactor from the air inlet. Under the action of the compressed air pressure, the mother liquid enters the liquid accumulation cavity from the filter surface and is discharged from the mother liquid outlet until the centrifugal filter disc is lowered to the lowest position; then the third valve and the fifth valve are reset and closed;

[0023] S4. Centrifugal unloading steps:

[0024] The centrifugal filter disc goes up to the high position again and starts to rotate; the fourth valve and the seventh valve are opened at the same time, and the compressed air enters the liquid accumulation chamber from the mother liquid outlet to back-blow the crystals from the back of the filter surface; under the coordinated action of centrifugal force and back-blow force, the filter cake layer formed by the crystals is removed from the filter surface and falls into the bottom of the stirring kettle through the reserved channel, and then all valves are reset and closed;

[0025] S5. Slag removal steps:

[0026] Open the slag outlet, and the crystals at the bottom of the stirring kettle are discharged from the slag outlet until the slag is completely discharged;

[0027] The rotation speed of the centrifugal filter disc in step S4 is higher than the rotation speed of the centrifugal filter disc in step S3.

[0028] The beneficial effects of this application are:

[0029] Through the above scheme, during the feeding, reaction, aging and crystallization stages, the centrifugal filter disc can ensure a high position by its own rising action, so that the material is mixed and crystallized below the centrifugal filter disc to form a mixed liquid that combines mother liquor and crystals, and will not cause clogging of the mesh at the filtering surface of the centrifugal filter disc. When filtering and dehydration is required, the centrifugal filter disc descends with a rotating action, and then immerses in the mixed liquid; the mixed liquid produces a liquid surface agitation under the stirring action of the centrifugal filter disc, so that the mixed liquid gradually ascends to the filtering surface through the reserved channel to achieve solid-liquid separation and filtration operations, and the generated mother liquor is extracted through the mother liquor cavity, and the filter cake is left on the filter layer. At this time, the reserved channel, in addition to serving as a mixed liquid channel, can also play the role of liquid rectification and current limiting, so that the reacted mixed liquid ascends in layers and batches, and is filtered in sequence after stabilizing the flow to ensure the filtering effect. As the centrifugal filter disc continues to descend, the mixed liquid is continuously separated into layers and batches of solids and liquids until all filtering operations are completed. Afterwards, the centrifugal filter disc rotates at high speed, so that the filter cake on the filtering surface of the upper disc of the centrifugal filter disc is centrifugally thrown off, and then falls to the bottom of the reactor through the reserved channel, finally realizing the crystal bottom recovery operation; obviously, the reserved channel now also takes into account the function of the crystal falling channel.

[0030] At the same time, the application provides a complete set of pipeline layouts for the most efficient matching of the stirred tank and the centrifugal filter disc, which ensures the most simplified pipeline layout while ensuring the stable operation of the centrifugal filter disc. Practice has shown that by relying on the coordination of various material sources, compressed air sources, and various switch valves, the crystals are quickly discharged from the bottom of the tank, and the mother liquor is quickly discharged to the mother liquor collection device, and the overall operating performance can be maximized.

[0031] It can be seen that the present application can realize multiple functions such as reaction, crystallization, aging, filtration, and unloading through the above system; practice has proved that the present application is particularly suitable for the diameter of more than 3000mm and the volume of more than 8m 3 , solid-liquid centrifugal separation operation of reaction aging crystallization in high parameter scenarios with slag volume greater than 3t. The overall structure and pipeline layout of this application are compact, simple in structure, and highly mechanized, which can effectively reduce equipment costs and operation and maintenance costs, with significant results. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the structure of the centrifugal unloading filter device of the present application;

[0033] Figure 2 for Figure 1 A local enlarged view of part I;

[0034] Figure 3 is a top view schematic diagram of a centrifugal filter disc;

[0035] Figure 4 This is a bottom view of the guide paddle;

[0036] Figure 5 , Figure 6 , Figure 7 , Figure 8 and Fig. 9 This is a working flow chart of the centrifugal unloading filtration equipment of this application;

[0037] Fig.10 This is a piping layout diagram of the centrifugal unloading filtration system of the present application.

[0038] The actual correspondence between the reference numbers and component names in this application is as follows:

[0039] N1-first feed port; N2-second feed port; N3-air inlet; N4-mother liquor outlet; N5-exhaust port; N6-slag outlet;

[0040] V1-first valve; V2-second valve; V3-third valve; V4-fourth valve; V5-fifth valve; V6-sixth valve; V7-seventh valve;

[0041] a-reserved channel; b-fluid cavity;

[0042] 10-reactor; 11-jacket;

[0043] 20-centrifugal filter plate; 21-liquid accumulation plate; 22-circular perforated plate; 22a-separating bar; 23-filter screen; 24-material guide paddle; 24a-left arc plate; 24b-right arc plate;

[0044] 31-rotating shaft; 31a-transition channel; 31b-liquid guide tube; 31c-annular tube; 31d-connecting tube; 32-power motor;

[0045] 41-fixed frame; 42-piston cylinder. DETAILED DESCRIPTION

[0046] For ease of understanding, here we combine Figure 1-10 The specific structure and working mode of this application are further described as follows:

[0047] This application is divided into two parts: centrifugal unloading filter equipment and matching piping system, among which:

[0048] The centrifugal unloading filter equipment is mainly composed of a transmission component, a reciprocating component, a centrifugal filter disc 20 and a guide component, a reaction kettle 10 and a bracket. Figure 1. Among them, the transmission component, the centrifugal filter disc 20 and the reactor 10 are coaxially arranged, and the transmission component is mainly composed of a power motor 32 fixed on a fixed frame 41, a reducer, a bearing seat, etc., which are jointly placed on the reciprocating component relying on the fixed frame 41. The reciprocating component is composed of two piston cylinders 42, preferably a hydraulic cylinder, and is symmetrically arranged around the axis, so as to jointly support the transmission component and the centrifugal filter disc 20. Under the action of hydraulic pressure, the piston cylinder 42 can drive the transmission component and the centrifugal filter disc 20 to reciprocate up and down. In order to increase the stability of the reciprocating motion of the piston cylinder 42, it is possible to consider arranging a guide component, which is generally composed of two symmetrically arranged guide columns, so as to cooperate with the guide sleeve on the bearing seat of the transmission component. Since the guide column of the conventional guide component is rigid and parallel to the rotating shaft 31, the verticality of guiding the reciprocating motion of the centrifugal filter disc 20 can be ensured.

[0049] The reactor 10 is a closed container, which consists of a head, i.e., a cover, a straight section of a cylinder, and a bottom plate, i.e., the bottom of the reactor. It is a place for material reaction, crystallization, and other activities, and is generally designed as a pressure-bearing container. The reciprocating components and the guide components are installed on the head or the lid of the reactor 10, and are evenly spaced around the axis. The bracket is matched with the ear seat of the reactor 10 to support the entire device.

[0050] The end cap of the reactor 10 is provided with corresponding feed ports, air inlets, exhaust ports, etc., so as to be connected with the reactor cavity of the reactor 10; a slag outlet N6 is also provided at the center of the bottom of the reactor 10; the rotating shaft 31 is a hollow shaft, and the hollow inner cavity forms a transition channel 31a, and a mother liquid outlet N4 is provided at the top of the transition channel 31a. In order to control the opening and closing of the above pipe ports, each pipe port is also provided with a corresponding valve. The relevant inlets and outlets and valves will be described in detail later.

[0051] The appearance of the centrifugal filter disc 20 is shown in FIG. Figure 1-4 As shown, it is the core component of this application, and the following is a key description:

[0052] The circular orifice plate 22 of the centrifugal filter disc 20 is coaxially fixed to the rotating shaft 31. The circular orifice plate 22 is provided with a series of holes to form a liquid flow channel. The upper plate surface of the circular orifice plate 22 is a conical surface with a high center and low surroundings, and its outer diameter is smaller than the inner diameter of the reactor 10 to leave room for the liquid to flow. Figure 2 The reserved channel a shown. A metal filter 23 with a certain filtering accuracy or other filter screen 23 with a certain strength is fixed to the upper plate surface of the circular orifice plate 22, and the whole still maintains a conical surface after being fixed. The purpose of the design of the conical surface of the circular orifice plate 22 and the filter screen 23 is that when the crystals on the filter screen 23 accumulate into a filter cake, under the action of centrifugal force, the distance between the crystals and the filter screen 23 after centrifugal throwing is short, the resistance is small, and the crystals are more easily centrifugally thrown out and separated from the conical filter screen 23. The mesh accuracy of the filter screen 23 is selected according to the crystal particle size after the material reaction, ranging from microns to millimeters, and will not be repeated.

[0053] like Figure 2 As shown, the bottom of the circular orifice plate 22 is fixedly connected to the liquid collection tray 21. The liquid collection tray 21 is similar to a shallow bowl, and is enclosed with the lower plate surface of the circular orifice plate 22 to form a liquid collection cavity b. To ensure that the liquid is drained thoroughly, the center of the liquid collection tray 21 should be the lowest point, that is, the bottom shape of the liquid collection tray 21 is high around and lowest in the center. Figure 2 As shown, a liquid guide tube 31b is coaxially arranged at the bottom of the rotating shaft 31, the bottom end of which extends into the center of the liquid collection tray 21, and the top end is connected to the rotating joint. Figure 3 As shown, the annular tube 31c is arranged in the liquid accumulation tray 21 and is concentric therewith, and is then connected to the liquid guide tube 31b through the connecting tube 31d. The connecting tube 31d is generally arranged in multiple pieces so that the gas can be discharged evenly and quickly, and the upper part of the annular tube 31c is evenly provided with spray holes on the side facing the filter screen 23. With such an arrangement, when it is necessary to back-blow the filter screen 23, the fifth valve V5 is closed, the fourth valve V4 is opened, and the compressed air enters the liquid guide tube 31b from the mother liquid outlet, enters the annular tube 31c through the connecting tube 31d, and is blown toward the back of the filter screen 23 through the spray holes. The back-blow force is relatively uniform, and the filter screen 23 is better stressed. Furthermore, in order to better protect the filter screen 23, a partition bar 22a can be set on the upper surface of the circular orifice plate 22; at this time, the partition bar 22a evenly divides the upper surface of the circular orifice plate 22 into a series of equal parts, such as Figure 3 The filter screen 23 is divided into six equal parts, each of which is fixed with a fan-shaped sub-net segment. Through the partition design, each sub-net segment is fixed with the adjacent partition fence 22a, which can bear a larger back-blowing force and have a better back-blowing effect; each sub-net segment is combined to form a conical filter screen 23.

[0054] At this point, the backblowing of the lower surface of the filter 23 and the conical centrifugal action of the upper surface of the filter 23 are combined to effectively solve the phenomenon of some crystals forming a dense crystal layer on the upper surface of the filter 23; under this working condition, the binding force between the crystals and between the crystals and the filter 23 is large, and it is difficult to remove. The actual solution is: first, backblowing the lower surface of the filter 23 for a certain period of time, or pulse backblowing can be adopted to blow up the dense crystal layer and loosen it; while backblowing, the centrifugal filter disc 20 is driven by the transmission components to rotate at high speed, and the crystals are subjected to the centrifugal force, and then rely on the conical structure of the upper surface of the filter 23 to make the crystals easier to fall off. The reason for this is that, on the one hand, one of the centrifugal force components acts vertically on the upper surface of the filter 23 and upward, that is, an upward pulling force is generated on the crystal, thereby reducing the friction between the crystal and the filter 23; on the other hand, after the crystal is centrifugally thrown out, because the upper surface of the filter 23 is conical, the crystal will immediately detach from the filter 23 without causing path interference on the upper surface of the filter 23, resulting in a better shedding effect.

[0055] Further, such as Figure 1 and Figure 4As shown, a guide paddle 24 is also provided at the bottom of the liquid accumulation tray 21. Because the entrance of the slag outlet N6 of the crystal is located at the center of the bottom of the reactor 10, the guide paddle 24 must have the function of guiding the crystal from the periphery to the center under the action of rotation. Figure 4 As shown, in actual design, the left arc plate 24a can be arranged to be circular and located on one side of the rotation direction, and the arc is located at the outer end, which has the function of collecting solids to the center, and the tangent direction of the end of the left arc plate 24a extends to the entrance center of the slag outlet N6; similarly, the right arc 24b and the left arc plate 24a are arranged symmetrically with the center, so that the left arc plate 24a and the right arc 24b together constitute an "S"-shaped material guide paddle 24. At this time, once the rotating shaft 31 rotates, the crystals can be scraped from the surroundings to the center, and finally discharged out of the machine from the slag outlet N6.

[0056] For further understanding of this application, Figure 5-10 , in conjunction with the pipeline system of this application, the typical operation process of this application is described in detail as follows:

[0057] Before starting the machine, it is necessary to check the equipment status, valve status, material conditions, position status of each component, etc. of this application; of course, the equipment can be self-checked through the control system with the help of corresponding sensor signals.

[0058] Then, the actual process is as follows:

[0059] 1) Feed / Reaction

[0060] Will be like Fig.10 The first valve V1 and the second valve V2 are opened, the first material enters the reactor 10 from the first feed port N1, and the second material enters the reactor 10 from the second feed port N2. Figure 5 As shown. Of course, the process may be to feed one material in front of the other; it may also be that a portion of the first material is fed first, and then a portion of the second material is fed, and then the cycle is repeated until the feed amount reaches the process requirement; it may also be fed at the same time; the specific feeding method, feeding ratio, and feeding amount are determined by the process, or are achieved with the help of flow meters, metering pumps, or liquid level meters, etc., which will not be elaborated here.

[0061] The two materials react after entering the reactor 10. According to the reaction requirements, the reactor 10 can be heated or cooled by the jacket 11 provided outside the reactor 10; the seventh valve V7 can be opened to discharge the gas or hot steam generated by the reaction through the exhaust port N5; the third valve V3 can be opened to discharge inert gas through the air inlet N3 for protection.

[0062] After the feeding is completed, all valves are reset and closed.

[0063] 2) Aging / Crystallization

[0064] As the materials in the kettle react, crystals will gradually precipitate, such as Figure 6 As shown; after a certain aging time, the crystals gradually grow in the mother liquor according to the process requirements. Similarly, the jacket 11 provided at the reactor 10 can be used for heating or cooling to control the process temperature required for aging / crystallization. Because the centrifugal filter disc 20 is at a high position, the reactants cannot contact the filter screen 23, and the crystals will not block the filter screen 23, thus solving the technical problem of clogging the filter medium during crystallization of the existing filter equipment.

[0065] 3) Filter pressing and dehydration

[0066] like Figure 7 As shown, when the reaction is completed, the centrifugal filter disc 20 in the high position is controlled to move downward under the action of the reciprocating component, gradually contacting the mixture of the mother liquid and the crystal, and at the same time rotating under the action of the transmission component. The speed can be set by the frequency converter to adjust the speed. In this section, the speed of the centrifugal filter disc 20 should not be too fast, but should be medium and slow. Subsequently, the third valve V3 and the fifth valve V5 are opened, and compressed air of a certain pressure enters the reactor 10 from the air inlet N3. Under the action of the compressed air pressure, the mother liquid enters the liquid accumulation chamber b through the filter screen 23 through the circular orifice plate 22, and then enters the annular tube 31c and even the liquid guide tube 31b in sequence through the spray hole, and finally is discharged from the mother liquid outlet N4 on the rotary joint. During the filter pressing process, the centrifugal filter disc 20 rotates at a medium and low speed, and the crystals are difficult to deposit on the surface of the filter screen 23, that is, a dynamic filtering behavior is performed, which ensures that the filter screen 23 always maintains a good filtering performance during the filter pressing process.

[0067] Until the centrifugal filter disc 20 Figure 7 As shown, the mother liquor is basically filtered out. At this time, most of the crystals are deposited on the surface of the filter screen 23 to form a filter cake; a small part of the crystals are deposited on the bottom plate of the reactor 10. During the filter pressing process, for safety reasons, a pressure gauge or pressure sensor, a safety valve, etc. can be set on the head of the reactor 10. If the filter cake needs to be washed in the process, an appropriate amount of washing liquid can be introduced from the corresponding pipe port, stirred and mixed through the centrifugal filter disc 20, and then pulped and washed, and then filtered. The number of washing times is set according to needs and will not be repeated.

[0068] After the filter pressing and dehydration are completed, the third valve V3 and the fifth valve V5 are reset and closed.

[0069] 4) Centrifugal unloading

[0070] The centrifugal filter disc 20 moves upward to a high position under the action of the reciprocating components, and can be adjusted by the frequency converter, so that the centrifugal unloading speed reaches the highest speed and the centrifugal force generated is also the largest. Depending on the characteristics of the crystal material, backblowing may or may not be required. Open the fourth valve V4 and the seventh valve V7, and the compressed air enters the liquid accumulation chamber b from the mother liquid outlet N4, and backblowing is performed on the crystal from the back of the filter screen 23. Under the combined action of centrifugal force and backblowing force, as shown in FIG. Figure 8 As shown, the filter cake layer formed by the crystals is unloaded from the conical surface of the filter screen 23. After the unloading is completed, each valve is reset and closed.

[0071] 5) Slag discharge

[0072] The centrifugal filter disc 20 moves downward under the action of the reciprocating components, and can be adjusted by the frequency converter to reach the scraping low speed. The sixth valve V6 is opened, and the slag discharge channel located at the bottom center of the reactor 10 is opened; under the action of the guide paddle 24, the crystals are scraped from the periphery to the center, and discharged from the machine through the slag discharge channel through the slag discharge port N6 where the sixth valve V6 is located. Fig. 9 To ensure smooth discharge, the bottom plate of the reactor 10 can be designed as a cone-shaped bottom plate, which is high around and low in the middle, and the slag discharge channel is located in the center of the bottom plate. To ensure complete scraping, the bottom shape of the guide paddle 24 and the cone-shaped bottom plate of the reactor 10 match each other to ensure their fit.

[0073] After the slag is discharged, the sixth valve V6 is closed, and a cleaning liquid may be introduced to perform CIP cleaning on the inside of the reactor 10 before the next cycle operation is performed.

[0074] All the above operations can be easily programmed, automated and intelligent under the control of the control system program.

[0075] Of course, for those skilled in the art, the present application is not limited to the details of the above exemplary embodiments, but also includes the same or similar methods that can be implemented in other specific forms without departing from the spirit or basic features of the present application. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present application is limited by the attached claims rather than the above description.

[0076] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0077] The technical parts not described in detail in this application are all well-known technologies.

Claims

1. A filtration system with reaction, aging and crystallization functions, comprising a reaction kettle (10) mounted on a support, characterized in that: It also includes a centrifugal filter disc (20) located in the reactor (10) and capable of rotating and lifting, wherein a reserved channel (a) is provided between the disc edge of the centrifugal filter disc (20) and the inner wall of the reactor (10) for the upward movement of materials and the downward movement of filter cakes; the upper disc surface of the centrifugal filter disc (20) has a filtering surface, and the reactor cavity of the reactor (10) is connected to the liquid accumulation cavity (b) located in the centrifugal filter disc (20) through the filtering surface, and the liquid accumulation cavity (b) is discharged to the mother liquid collection device through the transition channel (31a) and the mother liquid outlet (N4) in sequence, and a slag outlet (N6) connected to the crystallization collection device is arranged at the bottom of the reactor (10); The first material source is connected to the first material inlet (N1) of the stirring kettle (10) through a first material pipeline with a first switch valve (V1), the second material source is connected to the second material inlet (N2) of the stirring kettle (10) through a second material pipeline with a second switch valve (V2), and the compressed air source is connected to the air inlet (N3) through a compressed air pipeline with a third switch valve (V3); an air outlet (N5) is also arranged at the stirring kettle (10), and the air outlet (N5) is connected to the gas collection device via a seventh switch valve (V7); a fifth switch valve (V5) is arranged between the mother liquid outlet (N4) and the mother liquid collection device, and a bridging branch with a fourth switch valve (V4) is bridged between the inlet of the fifth switch valve (V5) and the outlet of the compressed air source.

2. The filtration system with reaction, aging and crystallization function according to claim 1, characterized in that: It also includes a sixth switch valve (V6) for controlling the on and off of the slag outlet (N6), and the power of the sixth switch valve (V6) comes from a compressed air source.

3. The filtration system with reaction aging and crystallization function according to claim 1, characterized in that: The filter surface is in the shape of a cone that gradually descends from the axis of the centrifugal filter disc (20) toward the disc edge.

4. The filtration system with reaction aging and crystallization function according to claim 1, characterized in that: A material guiding paddle (24) is arranged at the bottom of the centrifugal filter disc (20) for guiding the filter cake toward the direction of the slag outlet (N6) at the axis of the bottom of the kettle.

5. The filtration system with reaction aging and crystallization function according to any one of claims 1 to 4, characterized in that: The centrifugal filter disc (20) comprises a liquid accumulation disc (21) and a circular perforated plate (22) covering the disc opening of the liquid accumulation disc (21); the area enclosed by the lower plate surface of the circular perforated plate (22) and the disc cavity of the liquid accumulation disc (21) forms the liquid accumulation cavity (b); the upper plate surface of the circular perforated plate (22) is in the shape of a cone that gradually descends from the axis to the disc edge; the filter screen (23) is fixed to the upper plate surface in a covering manner; and the upper surface of the filter screen (23) constitutes the filtering surface.

6. The filtration system with reaction, aging and crystallization function according to claim 5, characterized in that: The centrifugal filter disc (20) is installed on the lid of the reactor (10) via a rotating shaft (31) and is rotated by a power motor (32); a hollow cavity is coaxially arranged inside the rotating shaft (31), and the hollow cavity constitutes a transition channel (31a) for the mother liquid and back-blowing gas flow to flow; the bottom of the hollow cavity extends to the lowest point of the liquid accumulation chamber (b) via a liquid guide tube (31b), and the top of the hollow cavity is connected to an external device via a rotating joint.

7. The filtration system with reaction, aging and crystallization function according to claim 6, characterized in that: An annular tube (31c) is coaxially installed near the edge of the liquid accumulation disk (21); the wall of the annular tube (31c) and the wall of the liquid guide tube (31b) are connected to each other via a radially extending connecting tube (31d); and a spray hole is arranged on the side of the annular tube (31c) facing the filter surface.

8. The filtration system with reaction, aging and crystallization function according to claim 5, characterized in that: The upper surface of the circular orifice plate (22) is provided with a partition bar (22a) for equally dividing the upper surface; in the circumferential direction of the circular orifice plate (22), two adjacent groups of partition bars (22a) form a fixed area for fixing the fan-shaped sub-net segments; each sub-net segment is assembled together at the upper plate surface of the circular orifice plate (22) to form a filter screen (23).

9. The filtration system with reaction, aging and crystallization function according to claim 5, characterized in that: The power motor (32) is mounted on a fixing frame (41); it also includes a piston cylinder (42), the two ends of which are respectively fixed to the fixing frame (41) and the cover of the reaction kettle (10), so that the centrifugal filter disc (20) is driven to produce a lifting action through the stroke action of the piston cylinder (42); and it also includes a guide column for guiding the moving direction of the centrifugal filter disc (20).

10. A filtration method, wherein the filtration system having the reaction aging crystallization function as claimed in any one of claims 1 to 4 is used, characterized in that The following steps are involved: S1. Feeding and reaction steps: The first valve (V1) and the second valve (V2) are opened, the first material enters the reactor (10) from the first feed port (N1), and the second material enters the reactor (10) from the second feed port (N2), then all valves are reset and closed, the two materials are mixed to form a mixed liquid and start to react; S2. Aging and crystallization steps: As the materials in the kettle react, crystals gradually precipitate and grow, and at this time, the centrifugal filter disc (20) remains in a high position without contacting the mixed liquid; S3. Filter pressing and dehydration step: At this time, the centrifugal filter disc (20) at a high position is controlled to move downward, contact the mixture, and generate a rotational motion at the same time, so that the mixed liquid is agitated and moves upward to the filtering surface through the reserved channel (a); then, the third valve (V3) and the fifth valve (V5) are opened, and compressed air enters the reaction kettle (10) from the air inlet (N3), and the mother liquid enters the liquid accumulation chamber (b) from the filtering surface under the action of the compressed air pressure, and is then discharged from the mother liquid outlet (N4) until the centrifugal filter disc (20) is lowered to the lowest position; then, the third valve (V3) and the fifth valve (V5) are reset and closed; S4. Centrifugal unloading steps: The centrifugal filter disc (20) moves upward to a high position again and starts to rotate; the fourth valve (V4) and the seventh valve (V7) are opened at the same time, and compressed air enters the liquid accumulation chamber (b) from the mother liquid outlet (N4) to back-blow the crystals from the back of the filter surface; under the coordinated action of centrifugal force and back-blow force, the filter cake layer formed by the crystals is removed from the filter surface and falls into the bottom of the stirring tank (10) through the reserved channel (a), and then the valves are reset and closed; S5. Slag removal steps: The slag discharge port (N6) is opened, and the crystals at the bottom of the stirring tank (10) are discharged from the slag discharge port (N6) until the slag is completely discharged; The rotation speed of the centrifugal filter disc (20) in step S4 is higher than the rotation speed of the centrifugal filter disc (20) in step S3.

Images