Continuous filtration and concentration discharge system and method

Abstract

The invention provides a continuous filtration and concentration discharge system and method, and belongs to the technical field of separation. The system comprises a filter, a membrane separation assembly and a sedimentation flow guide pipe; the filter is provided with a feed port and a discharge port, and the discharge port is connected with a concentrated phase collecting tank through a pipeline; a clear liquid discharge pipe is arranged at the side part of the filter; the clear liquid side of the membrane separation assembly is communicated with a clear liquid discharge pipe; the sedimentation guide pipe is positioned in the filter; the top end of the sedimentation flow guide pipe is connected to the position of the feeding hole, and the bottom end of the sedimentation flow guide pipe downwards extends below the bottom of the membrane separation assembly; solid-liquid mixed feed liquid moves to the position below the membrane separation assembly after passing through the feed port and the sedimentation flow guide pipe, and the feed liquid can upwards immerse the membrane separation assembly so as to reduce the solid content of the feed liquid around the membrane separation assembly; compared with an existing dead-end filtering mode, the dead-end filtering mode can be continuously operated; compared with an existing cross-flow filtering mode, the filtering efficiency of the dead-end filtering mode is higher than that of the cross-flow filtering mode.

Description

Technical Field

[0001] The present application belongs to the field of separation technology, and specifically relates to a continuous filtration and concentration removal system and method. Background Art

[0002] There are two conventional membrane filtration methods, one is dead-end filtration and the other is cross-flow filtration.

[0003] In dead-end filtration, the liquid is outside the membrane. Under pressure, particles larger than the membrane pores are trapped on the membrane surface, forming a filter cake. The filter cake also serves a certain retention function. As filtration time increases, the filter cake thickness increases. Dead-end filtration can form a filter cake with a high solids content. As filtration resistance increases, the membrane's filtration performance gradually decreases. Therefore, dead-end filtration can only be performed intermittently, and the filter cake layer on the membrane surface must be periodically removed.

[0004] In cross-flow filtration, the fluid flows along the inner side of the membrane along its axis, generating two forces on the membrane surface: a normal force perpendicular to the membrane, which forces the fluid to pass through the membrane surface; and a tangential force parallel to the membrane surface, which flushes away retained materials. When the membrane's filtration performance decreases, reducing the normal force and increasing the tangential force can effectively clean the membrane and restore its filtration performance. To meet the required tangential force on the membrane surface, the solids content of the cross-flow filtration fluid is relatively low, generally below 25%, resulting in low concentration efficiency.

[0005] From the perspective of filtration, dead-end filtration is simple to operate and has high filtration efficiency, but the filter cake has a high solid content and can only be carried out intermittently; cross-flow filtration achieves continuous operation, but the circulation volume is large, the fluid solid content is low, and the filtration efficiency is low. Summary of the Invention

[0006] The embodiments of the present application provide a continuous filtration and concentration discharge system and method, aiming to provide a dead-end filtration method, which reduces the solid content of the fluid in the dead-end filtration method while keeping the filtration flow rate unchanged, and enables the dead-end filtration method to operate continuously.

[0007] To achieve the above objectives, the technical solution adopted in this application is: Provided is a continuous filtration and concentration removal system, comprising: The filter has a feed port and a discharge port at the top and bottom respectively, and the discharge port is connected to a dense phase collection tank through a pipeline; the side of the filter has a clear liquid discharge pipe; At least two membrane separation modules are installed inside the filter; the clear liquid side of the membrane separation module is connected to the clear liquid discharge pipe, and the filtration mode of the membrane separation module is dead-end filtration; A sedimentation guide pipe is located inside the filter; the top end of the sedimentation guide pipe is connected to the feed inlet, and the bottom end of the sedimentation guide pipe extends downward to below the bottom of the membrane separation assembly; The solid-liquid mixture moves to the bottom of the membrane separation component after passing through the feed port and the sedimentation guide pipe. The mixture can immerse the membrane separation component upward to reduce the solid content of the mixture around the membrane separation component.

[0008] In a possible implementation, the diameter of the sedimentation guide pipe gradually increases from the top to the bottom, so as to reduce the flow rate at the outlet of the sedimentation guide pipe.

[0009] In one possible implementation, the ratio of the diameter of the feed port to the diameter of the filter is in the range of 1:5 to 1:30; the ratio of the flow rate at the feed port to the flow rate inside the filter is in the range of 1:25 to 1:900, so as to facilitate the downward sedimentation of solid materials.

[0010] In a possible implementation, the side of the dense phase collection tank has a first communication port, the side of the filter bottom has a second communication port, a circulation pipeline is connected between the first communication port and the second communication port, and a circulation pump is provided on the circulation pipeline; Wherein, driven by the circulation pump, the concentrated slurry at the bottom of the filter flows to the dense phase collection tank, and the concentrated slurry in the dense phase collection tank flows into the filter through the circulation pipeline to reduce blockage between the filter and the dense phase collection tank.

[0011] In one possible implementation, the filter is connected to the dense phase collection tank via a guide pipe, which extends into the interior of the dense phase collection tank; the first connecting port is located above the bottom end of the guide pipe, so that the upper layer of liquid in the dense phase collection tank enters the filter through the circulation pipeline.

[0012] In a possible implementation, the circulation volume of the circulation pipeline is 1 / 10-1 / 200 of the feed volume, and the maximum circulation volume is less than or equal to 500 L / h.

[0013] In a possible implementation, a side wall of the dense phase collection tank is provided with an observation window arranged along the axial direction to display the particle accumulation state inside the dense phase collection tank.

[0014] In a possible implementation, a recoil tank is further included, which is connected to the clear liquid discharge pipe through a recoil pipe, and a valve is provided on the recoil pipe; a compressed gas inlet is provided on the top of the recoil tank, and a valve is provided at the compressed gas inlet position.

[0015] In a possible implementation, the backwash liquid volume is 10-20 times the unit flux of a single membrane separation assembly, and the backwash width is 0.2-3s.

[0016] The present application provides a continuous filtration and concentration discharge system and method. Compared with the existing technology, the solid-liquid mixture entering the filter moves to the bottom of the membrane separation component under the action of the sedimentation guide tube, and the solid material settles at the bottom of the filter. The liquid level of the supernatant gradually rises and eventually submerges the membrane separation component. At this time, the membrane separation component filters the supernatant, which can reduce the solid content around the membrane separation component, and the filtrate is discharged from the clear liquid discharge pipe; the dense phase collection tank at the bottom of the filter can collect the settled solid material, and when the solid material in the dense phase collection tank reaches the preset requirements, the solid material in the dense phase collection tank is discharged; during the process of discharging the solid material, the filter works normally; compared with the existing dead-end filtration method, the above-mentioned dead-end filtration method of the present application can operate continuously; compared with the existing cross-flow filtration method, the filtration efficiency of the above-mentioned dead-end filtration method of the present application is higher than the filtration efficiency of the cross-flow filtration method.

[0017] To achieve the above purpose, another technical solution adopted in this application is: A continuous filtration and concentration removal method is provided, characterized in that it includes the following steps: The solid-liquid mixture moves to the bottom of the membrane separation component after passing through the feed inlet and the sedimentation guide pipe. The solid material settles at the bottom of the filter, and the liquid can move upward and immerse the membrane separation component to reduce the solid content of the liquid around the membrane separation component. The clear liquid after filtration by the membrane separation component is discharged from the clear liquid discharge pipe, and the solid materials settled at the bottom of the filter enter the dense phase collection tank through the pipeline; When the concentrated slurry in the dense phase collection tank meets the discharge requirements, close the valve connecting the dense phase collection tank and the filter to discharge the concentrated slurry in the dense phase collection tank; After the discharge is completed, fill the concentrated phase collection tank with liquid; Open the valve connecting the dense phase collection tank and the filter.

[0018] The beneficial effects of the continuous filtration and concentration removal method provided in this application are the same as the beneficial effects of the continuous filtration and concentration removal system, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic structural diagram of a continuous filtration and concentration removal system provided in an embodiment of the present invention; Figure 2 A schematic diagram of the structure of a filter settling guide tube and a membrane separation assembly provided in an embodiment of the present invention; Figure 3 A schematic structural diagram of a recoil valve combination mode of a recoil system provided by an embodiment of the present invention; Figure 4 Schematic diagram of the operation of the compensation cycle unit and particle concentration according to an embodiment of the present invention.

[0020] Explanation of the reference numerals: A, reaction liquid; B, filtrate discharge; C, dense phase discharge; D, compressed gas inlet; 1, filter; 11, membrane separation assembly; 111, membrane element; 112, drain pipe; 12, sedimentation guide pipe; 13, membrane assembly outlet; 2, backwash unit; 21, backwash tank; 22, clear liquid switch valve; 23, backwash switch valve; 3, dense phase collection tank; 4, compensation circulation unit; 41, circulation pump. DETAILED DESCRIPTION

[0021] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0022] Please also refer to Figures 1 to 4 , a continuous filtration and concentration drainage system and method provided by the present application will now be described. The continuous filtration and concentration drainage system comprises a filter 1, at least two groups of membrane separation modules 11, and a sedimentation guide pipe 12; the filter 1 has a feed port and a discharge port at the top and bottom, respectively, and the discharge port is connected to a dense phase collection tank 3 through a pipe; the side of the filter 1 has a clear liquid discharge pipe; the membrane separation module 11 is installed inside the filter 1; the clear liquid side of the membrane separation module 11 is connected to the clear liquid discharge pipe, and the filtration method of the membrane separation module 11 is dead-end filtration; the sedimentation guide pipe 12 is located inside the filter 1; the top end of the sedimentation guide pipe 12 is connected to the feed port, and the bottom end of the sedimentation guide pipe 12 extends downward to below the bottom of the membrane separation module 11; wherein, the solid-liquid mixed feed liquid moves to the bottom of the membrane separation module 11 after passing through the feed port and the sedimentation guide pipe 12, and the feed liquid can immerse the membrane separation module 11 upward to reduce the solid content of the feed liquid around the membrane separation module 11.

[0023] The present application provides a continuous filtration and concentration discharge system and method. Compared with the existing technology, the solid-liquid mixture entering the filter 1 moves to the bottom of the membrane separation component 11 under the action of the sedimentation guide tube 12, and the solid material settles at the bottom of the filter 1. The liquid level of the supernatant gradually rises and eventually submerges the membrane separation component 11. At this time, the membrane separation component 11 filters the supernatant, which can reduce the solid content around the membrane separation component 11, and the filtrate is discharged from the clear liquid discharge pipe; the dense phase collection tank 3 at the bottom of the filter 1 can collect the settled solid material, and when the solid material in the dense phase collection tank 3 reaches the preset requirements, the solid material in the dense phase collection tank 3 is discharged, that is, the dense phase discharge C; during the process of discharging the solid material, the filter 1 works normally; compared with the existing dead-end filtration method, the above-mentioned dead-end filtration method of the present application can operate continuously; compared with the existing cross-flow filtration method, the filtration efficiency of the above-mentioned dead-end filtration method of the present application is higher than the filtration efficiency of the cross-flow filtration method.

[0024] It should be noted that the membrane separation assembly 11 is arranged on the inner wall of the filter 1. Taking four groups of membrane separation assemblies 11 as an example, the four groups of membrane separation assemblies 11 are evenly arranged on the inner wall of the filter 1; the feed port is located in the middle position of the top of the filter 1, and the sedimentation guide pipe 12 is also located in the middle position inside the filter 1; through the above arrangement, the solid-liquid mixture liquid is guided to the middle position near the bottom of the filter 1 through the sedimentation guide pipe 12, which facilitates the solid material in the solid-liquid mixture liquid to diffuse from the middle of the filter 1 to the surrounding area and settle at the bottom of the filter 1. The solid material settled at the bottom of the filter 1 is collected by the dense phase collection tank 3, which can reduce the solid material accumulated at the bottom of the filter 1.

[0025] When discharging the solid material from the dense phase collection tank 3, the dense phase collection tank 3 is disconnected from the filter 1. Therefore, the discharge process of the dense phase collection tank 3 does not affect the normal filtering process of the filter 1. After the dense phase collection tank 3 is discharged, the dense phase collection tank 3 is filled with liquid, and then the valve connecting the dense phase collection tank 3 and the filter 1 is opened, so that the solid material at the bottom of the filter 1 moves into the dense phase collection tank 3. This liquid replenishment operation can reduce the disturbance after the dense phase collection tank 3 and the filter 1 are connected.

[0026] Specific description of membrane separation assembly 11: Each membrane separation assembly 11 includes a row pipe 112 and several membrane elements 111 connected to the row pipe 112. The row pipe 112 is connected to the clear liquid discharge pipe. During operation, the membrane elements 111 filter the feed liquid. The filtrate enters the membrane element 111 and ultimately enters the row pipe 112. It is discharged from the filter 1 through the clear liquid discharge pipe, i.e., the clear liquid discharge B. The outer end of the row pipe 112 is the membrane assembly outlet 13. The membrane elements 111 are a combination of one or more metal sintered powder filter elements, sintered felt filter elements, multi-layer mesh filter elements, and wedge mesh filter elements.

[0027] Specific description of the dense phase collection tank 3: The dense phase collection tank 3 is located at the lower part of the filter 1. The dense phase collection tank 3 is connected to the filter 1 through a guide pipe. The discharge port at the bottom of the dense phase collection tank 3 is in a normally closed state. The discharge port at the bottom of the dense phase collection tank 3 is opened only when discharge is required. The solid material content in the filter 1 is reduced by collecting and discharging the solid material in the dense phase collection tank 3.

[0028] In some embodiments, as Figures 1 to 4 As shown, the diameter of the sedimentation guide pipe 12 gradually increases from the top to the bottom, so as to reduce the flow velocity at the outlet of the sedimentation guide pipe 12 .

[0029] It should be noted that the solid-liquid mixture liquid enters the sedimentation guide tube 12 from the feed inlet of the filter 1, and during the movement in the sedimentation guide tube 12, the diameter of the sedimentation guide tube 12 gradually increases, so the speed of the solid-liquid mixture liquid decreases rapidly. After the solid-liquid mixture liquid enters the filter 1 from the bottom end of the sedimentation guide tube 12, the flow rate of the solid-liquid mixture liquid basically has no effect on the feed liquid around the membrane separation component 11, reduces fluid disturbance, and facilitates the sedimentation of solid materials at the bottom of the filter 1, thereby enhancing the sedimentation effect of solid materials, and thereby reducing the solid materials around the membrane separation component 11, thereby reducing the burden on the membrane separation component 11 and extending the filtration time of the membrane separation component 11.

[0030] In some embodiments, as Figures 1 to 4 As shown, the ratio of the diameter of the feed port to the diameter of the filter 1 is in the range of 1:5 to 1:30; the ratio of the flow rate at the feed port to the flow rate inside the filter 1 is in the range of 1:25 to 1:900, so as to facilitate the downward sedimentation of solid materials.

[0031] It should be noted that the ratio of the feed port diameter to the filter 1 diameter is between 1:5-1:30. This ratio can ensure that the feed port is smaller in size relative to the filter 1 body; the smaller feed port can form a relatively stable fluid environment inside the filter 1, and can transport the fluid containing solid materials into the filter 1 at a relatively small flow rate; in this way, it will not cause excessive turbulence inside the filter 1, making it easier for solid materials to settle downward in a relatively stable fluid state.

[0032] Since the feed port is small, the incoming fluid speed will be faster, but since the internal space of the filter 1 is large, the fluid speed will decrease rapidly during the diffusion process, thereby reducing the fluid drag force on the solid material, which is conducive to the solid material settling downward under the action of gravity.

[0033] The ratio of the flow rate at the feed inlet to the flow rate inside the filter 1 is between 1:25 and 1:900. Such a flow rate ratio can effectively control the movement state of the solid material in the filter 1. When the flow rate at the feed inlet is high and the flow rate drops rapidly after entering the filter 1, the solid material will continue to move a certain distance into the filter 1 due to inertia. However, as the flow rate decreases, the upward fluid resistance it encounters will also decrease. At this time, under the action of gravity, the solid material can settle downward more easily, thereby improving the filtration efficiency.

[0034] In some embodiments, as Figures 1 to 4As shown, it also includes a compensating circulation unit 4, the side of the dense phase collection tank 3 has a first connecting port, and the side of the bottom position of the filter 1 has a second connecting port, the compensating circulation unit 4 includes a circulation pipeline connected to the first connecting port and the second connecting port and a circulation pump 41, and the circulation pump 41 is connected to the circulation pipeline; wherein, under the drive of the circulation pump 41, the concentrated slurry at the bottom of the filter 1 flows to the dense phase collection tank 3, and the concentrated slurry in the dense phase collection tank 3 flows from the circulation pipeline to the filter 1 to reduce blockage between the filter 1 and the dense phase collection tank 3.

[0035] It should be noted that after starting the circulation pump 41, the solid material at the bottom of the filter 1 can flow into the dense phase collection tank 3, thereby reducing the solid material that is compacted at the bottom of the filter 1 and reducing the solid material that is compacted in the pipe connecting the filter 1 and the dense phase collection tank 3. Therefore, the above-mentioned circulation flow method can reduce the occurrence of blockages and facilitate the discharge of the solid material in the filter 1 into the dense phase collection tank 3.

[0036] In some embodiments, as Figures 1 to 4 As shown, the filter 1 is connected to the dense phase collection tank 3 through a guide pipe, which extends into the dense phase collection tank 3; the first connecting port is located above the bottom end of the guide pipe, so that the upper layer of liquid in the dense phase collection tank 3 enters the filter 1 through the circulation pipeline.

[0037] It should be noted that, by inserting the guide tube into the position near the bottom of the dense phase collection tank 3, after driving the circulation pump 41, the solid material in the filter 1 enters the position near the bottom of the dense phase collection tank 3 along the guide tube; and the first connecting port is located above the bottom end of the guide tube. Therefore, the material entering the filter 1 from the circulation pipeline is the material near the top of the dense phase collection tank 3, and the solid content of the material at the top of the dense phase collection tank 3 is lower than the solid content of the material at the bottom of the dense phase collection tank 3, thereby reducing the concentrated slurry entering the filter 1.

[0038] In some embodiments, as Figures 1 to 4 As shown, the circulation volume of the circulation pipeline is 1 / 10-1 / 200 of the feed volume, and the maximum circulation volume is less than or equal to 500L / h.

[0039] It should be noted that the circulation volume of the circulation pipeline is less than the feed volume. On the premise of ensuring that the solid material between the filter 1 and the dense phase collection tank 3 can circulate, more liquid is allowed to exist in the filter 1, thereby facilitating the upper layer of the solid-liquid mixed liquid to immerse the membrane separation component 11, and then the upper layer of the liquid is filtered through the membrane separation component 11.

[0040] In some embodiments, as Figures 1 to 4 As shown, the side wall of the dense phase collection tank 3 has an observation window arranged along the axial direction to display the particle accumulation state inside the dense phase collection tank 3.

[0041] It should be noted that by providing an observation window on the side wall of the dense phase collection tank 3, the operator can observe the particle accumulation in the dense phase collection tank 3, thereby making it easier for the operator to decide whether to discharge the solid material in the dense phase collection tank 3 according to actual conditions.

[0042] In some embodiments, as Figures 1 to 4 As shown, the recoil unit 2 is also included. The recoil unit 2 includes a recoil tank 21. The recoil tank 21 is connected to the clear liquid discharge pipe through a recoil pipe, and a valve is provided on the recoil pipe. The top of the recoil tank 21 is provided with a compressed gas inlet D, and a valve is provided at the position of the compressed gas inlet D. The recoil liquid volume is 10-20 times the unit flux of a single membrane separation assembly 11, and the recoil width is 0.2-3s.

[0043] It should be noted that the backwash pipeline includes several branch pipelines, each of which is connected to the clear liquid side of one group of membrane separation components 11; when a group of membrane separation components 11 needs to be backwashed, the clear liquid switch valve 22 of the clear liquid outlet of the group is closed, and the valve on the branch pipeline of the group is opened. The liquid in the backwash tank 21 passes through the membrane element 111 of the membrane separation component 11 under the action of gas pressure, removes the filter cake on the outer peripheral wall of the membrane element 111, and the flux of the membrane element 111 is restored, and filtration can continue; after the backwash is completed, the backwash tank 21 is replenished with the filtered clear liquid of the membrane separation component 11, and after the replenishment is completed, the valve on the branch pipeline is closed; the valve on the branch pipeline is the backwash switch valve 23.

[0044] Each backflushing of the membrane separation components 11 is performed in one group. When the membrane separation components 11 in one group are backflushed, the other groups of membrane separation components 11 perform normal filtration. With the above arrangement, the continuous operation of dead-end filtration can be achieved, and the filtration process is smoother.

[0045] Based on the same inventive concept, the present application also provides a continuous filtration and concentration discharge method, comprising the following steps: The solid-liquid mixture moves to the bottom of the membrane separation component 11 after passing through the feed port and the sedimentation guide pipe 12. The solid material settles at the bottom of the filter 1. The liquid can move upward and immerse the membrane separation component 11 to reduce the solid content of the liquid around the membrane separation component 11.

[0046] The clear liquid filtered by the membrane separation assembly 11 is discharged from the clear liquid discharge pipe, and the solid materials settled at the bottom of the filter 1 enter the dense phase collection tank 3 through the pipeline.

[0047] When the concentrated slurry in the dense phase collecting tank 3 meets the discharge requirement, the valve connecting the dense phase collecting tank 3 and the filter 1 is closed to discharge the concentrated slurry in the dense phase collecting tank 3 .

[0048] After the discharge is completed, the dense phase collection tank 3 is filled with liquid.

[0049] Open the valve connecting the dense phase collection tank and the filter.

[0050] Example 1: Continuous Filtration and Concentration of Ethyl Methyl Oxalate Catalyst The system of the present invention is used to filter and concentrate ethyl methyl oxalate catalyst, comprising the following steps: a reaction liquid A enters from the top of a filter 1, with a pipe diameter of DN20, a flow rate of 0.5 m³ / h, a catalyst content of 5%, and a flow rate of 0.45 m / s; the filter 1 has a specification of DN700 and a filtration area of ​​3 m2; the membrane element 111 has a specification of φ50*1000 mm; the membrane separation assembly 11 has 6 groups; the inlet of the sedimentation guide pipe 12 has a DN40 inlet and a DN100 outlet; the reaction liquid A enters from the sedimentation guide pipe 12 into the bottom of the filter 1, and the flow rate gradually decreases from 0.45 m / s to 3.6*10-4 m / s, with the flow rate reduced by 1225 times.

[0051] The time it takes for the reaction liquid A in the filter 1 to move to the upper part of the membrane element 111 is 2777 seconds. During this period, approximately 70% of the catalyst particles have settled to the bottom of the filter 1. Under the microcirculation action of the circulation pump 4, the catalyst particles are collected by the dense phase collection tank 3. The settled reaction liquid A is separated into solid and liquid by the membrane separation component 11 to obtain the filtrate. The filter cake thickening rate is reduced by 70%, and the time required to obtain the same filter cake thickness is increased by 3.3 times.

[0052] Set the backwash interval and backwash width, and perform online backwash on the membrane separation components 11 one by one; by calculating the particle content of the dense phase collection tank 3, the dense phase is discharged within the set time, first disconnect the valve connecting the dense phase collection tank 3 and the filter 1, close the circulation pump 4, separate the dense phase collection tank 3 from the system, introduce the reaction liquid A into the dense phase collection tank 3, open the bottom valve, discharge the concentrated slurry, use flow control to discharge the concentrated liquid, close the bottom valve, turn off the reaction liquid A feed, open the valve connecting the dense phase collection tank 3 and the filter 1, start the circulation pump 4, and complete feeding, continuous filtration, backwashing, and concentrated slurry discharge.

[0053] Example 2: Polyolefin Concentration and Filtration The polyolefin reaction uses C6~8 as solvent. The polyolefin is fibrous and has a higher density than the solvent. After about 15 minutes of natural sedimentation, most of the polyolefin will settle to the bottom. The filter cake has poor air permeability. After testing, the dead-end filtration filter cake thickness reaches 1mm. When the filtration pressure difference is 400kpa, there is no flux. Although cross-flow filtration can maintain flux, the circulation volume is large and the filtration efficiency is low. The impeller shear, temperature rise and long residence time caused by the circulation have a greater impact on product quality.

[0054] The device of the present invention comprises the following steps: reaction liquid A enters the top of filter 1 through a DN20 pipe with a flow rate of 0.5 m³ / h, a polyolefin content of 1%, and a flow rate of 0.45 m / s. Filter 1 is DN600 with a filtration area of ​​2.5 m². The membrane elements 111 are φ50 x 1000 mm. The membrane separation assembly 11 is grouped into eight groups. The settling flow guide 12 has a DN40 inlet and a DN100 outlet. Reaction liquid A enters the bottom of filter 1 through settling flow guide 12, with the flow rate gradually decreasing from 0.45 m / s to 5 x 10⁻⁴ m / s, a 900-fold reduction. The reaction liquid A in filter 1 takes 2000 seconds to reach the top of membrane element 111, during which time approximately 80% of the catalyst particles have settled to the bottom of filter 1. Microcirculation by a circulating pump 4 collects the catalyst particles in a dense phase collection tank 3. After settling, the reaction liquid A is separated into solid and liquid by the membrane separation component 11 to obtain the filtrate. The rate of filter cake thickening is reduced by 80%, and the time required to obtain the same filter cake thickness is increased by 5 times. According to the filter cake thickness setting, the time of a single group of backwash tanks is increased from 20 minutes to 100 minutes. The backwash interval and backwash width are set, and the membrane separation components 11 are backwashed online one by one. By calculating the particle content of the dense phase collection tank 3, the dense phase is discharged within the set time. First, the valve connecting the dense phase collection tank 3 and the filter 1 is closed, the circulation pump 4 is turned off, and the dense phase collection tank 3 is separated from the system. The reaction liquid A is introduced into the dense phase collection tank 3, and the bottom valve is opened to discharge the concentrated slurry. The concentrated liquid is discharged using flow control. The bottom valve is closed, the reaction liquid A feed is closed, the connection between the dense phase collection tank 3 and the filter 1 is opened, and the circulation pump 4 is turned on to complete the feeding, continuous filtration, backwashing, and concentrated slurry discharge.

[0055] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A continuous filtration and concentration removal system, characterized in that: include: The filter has a feed port and a discharge port at the top and bottom respectively, and the discharge port is connected to a dense phase collection tank through a pipeline; The side of the filter is provided with a clear liquid discharge pipe; At least two membrane separation modules are installed inside the filter; the clear liquid side of the membrane separation module is connected to the clear liquid discharge pipe, and the filtration mode of the membrane separation module is dead-end filtration; A sedimentation guide pipe is located inside the filter; the top end of the sedimentation guide pipe is connected to the feed inlet, and the bottom end of the sedimentation guide pipe extends downward to below the bottom of the membrane separation assembly; The solid-liquid mixture moves to the bottom of the membrane separation component after passing through the feed port and the sedimentation guide pipe. The mixture can immerse the membrane separation component upward to reduce the solid content of the mixture around the membrane separation component.

2. A continuous filtration and concentration removal system according to claim 1, characterized in that: The diameter of the sedimentation guide pipe gradually increases from the top to the bottom, so as to reduce the flow rate at the outlet of the sedimentation guide pipe.

3. A continuous filtration and concentration removal system according to claim 1, characterized in that: The ratio of the diameter of the feed port to the diameter of the filter is in the range of 1:5 to 1:30; the ratio of the flow rate at the feed port to the flow rate inside the filter is in the range of 1:25 to 1:900, so as to facilitate the downward sedimentation of solid materials.

4. A continuous filtration and concentration removal system according to claim 1, characterized in that: The side of the dense phase collection tank has a first communication port, and the side of the bottom of the filter has a second communication port. A circulation pipeline is connected between the first communication port and the second communication port, and a circulation pump is provided on the circulation pipeline. Wherein, driven by the circulation pump, the concentrated slurry at the bottom of the filter flows to the dense phase collection tank, and the concentrated slurry in the dense phase collection tank flows into the filter through the circulation pipeline to reduce blockage between the filter and the dense phase collection tank.

5. A continuous filtration and concentration removal system according to claim 4, characterized in that: The filter is connected to the dense phase collection tank through a guide pipe, and the guide pipe extends into the dense phase collection tank; the first communication port is located above the bottom end of the guide pipe, so that the upper layer of liquid in the dense phase collection tank enters the filter through the circulation pipeline.

6. A continuous filtration and concentration removal system according to claim 4, characterized in that: The circulation volume of the circulation pipeline is 1 / 10-1 / 200 of the feed volume, and the maximum circulation volume is less than or equal to 500L / h.

7. The continuous filtration and concentration removal system according to claim 1, characterized in that: The side wall of the dense phase collection tank is provided with an observation window arranged along the axial direction to display the particle accumulation state inside the dense phase collection tank.

8. The continuous filtration and concentration removal system according to claim 1, characterized in that: It also includes a recoil tank, which is connected to the clear liquid discharge pipe through a recoil pipe, and a valve is provided on the recoil pipe; the top of the recoil tank is provided with a compressed gas inlet, and a valve is provided at the compressed gas inlet position.

9. A continuous filtration and concentration removal system according to claim 8, characterized in that: The backwash liquid volume is 10-20 times the unit flux of a single membrane separation component, and the backwash width is 0.2-3s.

10. A method for continuous filtration and concentration removal using the continuous filtration and concentration removal system according to any one of claims 1 to 9, characterized in that: The following steps are involved: The solid-liquid mixture moves to the bottom of the membrane separation component after passing through the feed inlet and the sedimentation guide pipe. The solid material settles at the bottom of the filter, and the liquid can move upward and immerse the membrane separation component to reduce the solid content of the liquid around the membrane separation component. The clear liquid after filtration by the membrane separation component is discharged from the clear liquid discharge pipe, and the solid materials settled at the bottom of the filter enter the dense phase collection tank through the pipeline; When the concentrated slurry in the dense phase collection tank meets the discharge requirements, close the valve connecting the dense phase collection tank and the filter to discharge the concentrated slurry in the dense phase collection tank; After the discharge is completed, fill the concentrated phase collection tank with liquid; Open the valve connecting the dense phase collection tank and the filter.

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