A brine filtration device for an epichlorohydrin production process

Abstract

The utility model relates to the technical field of chemical production equipment discloses a salt water filtering device for epoxy chloropropane production process, including pre -coating jar, agitator, candle type filter, bag type security filter, feed pump, pre -coating pump, back flushing valve and control cabinet, be equipped with suspension type filter candle in candle type filter, utilize pre -coating pump and establish pre -coating, bag type security filter is connected in series in clear liquid export and carries out two -stage interception, and compressed gas source is accessed to the pipeline in reverse through back flushing valve to realize filter core on -line regeneration, and control cabinet coordinates each component automatic operation, the utility model discloses a candle type and bag type cascade structure and gas back flushing technology, solved the problem of insufficient precision and cleaning difficulty of existing filtering equipment, has the beneficial effect of high filtration precision, filter core on -line regeneration exempts from disassembly and full -automatic operation.

Description

Technical Field

[0001] This utility model relates to the field of chemical production equipment technology, and in particular to a brine filtration device for epichlorohydrin production process. Background Technology

[0002] Epichlorohydrin is an important organic chemical raw material, and the quality of the brine produced or used in its production process is crucial to the stable operation of the entire system. During production, the process brine often contains a large number of suspended particles, colloidal substances, and some organic impurities. If these impurities cannot be effectively removed and directly enter the subsequent electrolysis or resin adsorption stages, it will lead to ion exchange membrane poisoning, increased electrolytic cell voltage, or resin pore blockage, severely shortening the lifespan of expensive equipment and increasing production costs.

[0003] Currently, for the treatment of such brine, existing technologies commonly employ plate and frame filter presses or ordinary bag filters for interception. However, while plate and frame filter presses have a large dirt-holding capacity, their sealing performance is relatively poor, making them prone to edge leakage. Furthermore, manual assistance is required during unloading and cleaning, resulting in high labor intensity and a harsh working environment, failing to meet the requirements of modern factories for automation and clean production. Ordinary bag filters, while relatively easy to operate, are prone to clogging when dealing with brine containing viscous organic matter, leading to frequent filter media replacements. This not only increases consumable costs but also causes production interruptions during replacement and carries the risk of bypass leakage due to improper installation, failing to guarantee a consistently stable high-precision filtration effect. In addition, existing single filtration methods lack effective online regeneration mechanisms and secondary protection measures. Once a filter element is damaged, impurities will directly penetrate and contaminate downstream areas, weakening the system's resilience.

[0004] Therefore, this utility model proposes a brine filtration device for epichlorohydrin production process to overcome the shortcomings of the prior art. Utility Model Content

[0005] In view of the problems existing in the brine filtration equipment used for epichlorohydrin production, such as unstable filtration accuracy, easy clogging of filter elements and high maintenance costs due to manual disassembly requiring shutdown for regeneration, and lack of secondary protection which can easily damage downstream precision equipment, this utility model aims to provide a brine filtration device for epichlorohydrin production process with an improved structure that can effectively solve the above problems.

[0006] This utility model provides a brine filtration device for epichlorohydrin production process, comprising: a pre-coating tank, a stirrer, a candle filter, a bag security filter, a feed pump, a pre-coating pump, a compressed gas source, a backflush valve, a slag discharge valve, and a control cabinet.

[0007] The stirrer is mounted on the pre-coating tank. The candle filter includes a cylindrical body, a perforated plate dividing the inner cavity of the cylindrical body into an upper chamber and a lower chamber, and a filter candle suspended from the perforated plate and extending into the lower chamber. The cylindrical body is provided with a raw liquid inlet communicating with the lower chamber and a clear liquid outlet communicating with the upper chamber.

[0008] Furthermore, the input end of the pre-coating pump is connected to the pre-coating tank, and the output end is connected to the raw liquid inlet. The output end of the feed pump is connected to the raw liquid inlet. The inlet of the bag filter is connected to the clear liquid outlet. The compressed gas source is connected to the pipeline where the clear liquid outlet is located via the backflush valve. The slag discharge valve is located at the bottom of the cylinder. The control cabinet is electrically connected to the agitator, feed pump, pre-coating pump, backflush valve, and slag discharge valve, respectively. Through this combination, a closed-loop control of the entire process from pre-coating and filtration to backflush regeneration is realized.

[0009] Preferably, the filter candle has a tubular structure, the outer surface of the filter candle is covered with a metal mesh, the internal channel of the filter candle passes through the perforated plate and communicates with the upper chamber, and the metal mesh is used to support the pre-coating layer and intercept impurities.

[0010] Preferably, the bag-type security filter is provided with a support basket and a filter bag located inside the support basket. The outlet of the bag-type security filter constitutes the clean liquid output end of the device, and the support basket prevents the filter bag from deforming under high pressure.

[0011] Preferably, the agitator includes a drive motor and an agitator blade extending into the pre-coating tank. The agitator blade is used to continuously mechanically agitate the filter aid slurry in the pre-coating tank to prevent solid particles from settling.

[0012] Preferably, a gas storage tank is provided between the compressed gas source and the backflush valve. When the backflush valve is opened, the gas in the gas storage tank enters the filter candle in reverse through the clear liquid outlet to peel off the filter cake, thereby improving the regeneration efficiency by utilizing pulsed airflow.

[0013] Preferably, a flow path switching valve is provided between the raw liquid inlet and the feed pump, and between the raw liquid inlet and the pre-coating pump. The flow path switching valve is electrically connected to the control cabinet and is used to isolate the fluids of different processes.

[0014] Preferably, the bottom of the cylinder has a conical structure, and the slag discharge valve is located at the lowest point of the conical structure, for smoothly discharging mixed waste residue containing salt, impurities and lignocellulose under the action of gravity.

[0015] Preferably, the control cabinet integrates a PLC controller, which is configured to automatically control the pre-coating pump to run the pre-coating process, control the feed pump to run the filtration process, and control the backflushing valve and slag discharge valve to run the backflushing and slag discharge process according to a preset timing sequence.

[0016] Preferably, the liquid-contacting parts of the cylinder, filter candle, and bag-type security filter are all made of corrosion-resistant materials to adapt to the highly corrosive environment of the epichlorohydrin production process.

[0017] This utility model has the following beneficial effects: 1. This utility model uses a candle filter as the main filtration unit and a pre-coating tank for pre-coating the filter aid. At the same time, a bag security filter is connected in series at the rear end of the clear liquid outlet to form a two-stage filtration structure. This solves the problem that existing single filtration equipment has insufficient filtration accuracy and is prone to filtration permeation, which can lead to impurities contaminating downstream precision equipment such as ion exchange membranes or electrolyzers when treating epichlorohydrin brine. It achieves a submicron-level precision filtration effect and provides double safety protection for the production process, ensuring the high cleanliness and stability of the final effluent water quality.

[0018] 2. This utility model, by setting up a backflush slag discharge system including a compressed gas source, a gas storage tank and a backflush valve, combined with the metal mesh structure on the surface of the candle filter, solves the problem that the filter element of traditional precision filtration equipment is easy to clog and difficult to clean, often requiring shutdown and disassembly for manual cleaning. It achieves the technical effect of using gas pulse to realize rapid filter cake peeling and online regeneration of filter element without disassembly, significantly reducing maintenance costs and improving production continuity.

[0019] 3. This utility model, by integrating a control cabinet and connecting it with the feed pump, pre-coating pump, agitator and various valves and electrical components, constructs an automated fluid control logic, which solves the problems of cumbersome manual operation, easy errors when switching between different processes, and difficulty in accurately controlling the filtration flow rate and pressure difference. It achieves a highly efficient production effect of fully automatic unattended operation and seamless connection between pre-coating, filtration and slag discharge in each process. Attached Figure Description

[0020] Figure 1 This is a three-dimensional schematic diagram of a brine filtration device for epichlorohydrin production process proposed in this utility model. Figure 2 This is a schematic diagram of the backflush valve of a brine filtration device for epichlorohydrin production process proposed in this utility model. Figure 3 This is a schematic diagram of the filter element of a brine filtration device for epichlorohydrin production process proposed in this utility model. Figure 4This is a schematic diagram of the structure of a bag-type security filter for a brine filtration device in the epichlorohydrin production process proposed in this utility model.

[0021] Legend: 1. Pre-coating tank; 2. Agitator; 3. Candle filter; 4. Cylinder; 5. Filter candle; 6. Perforated plate; 7. Raw material inlet; 8. Clear liquid outlet; 9. Bag security filter; 10. Feed pump; 11. Pre-coating pump; 12. Compressed gas source; 13. Backflush valve; 14. Slag discharge valve; 15. Control cabinet. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0023] Example: Please refer to Figures 1 to 4 This utility model provides a brine filtration device for epichlorohydrin production processes, which aims to solve the structural defects of existing epichlorohydrin brine filtration processes, such as insufficient filtration accuracy, difficulty in regenerating filter elements requiring frequent disassembly, and the tendency of a single filtration stage to cause downstream pollution.

[0024] like Figure 1 As shown, the main structure of the brine filtration device includes a pre-coating tank 1, a stirrer 2 installed above the pre-coating tank 1, a candle filter 3 as the main filtration unit, a bag filter 9 as the secondary protection unit, and supporting fluid transport and control components. The components are connected by pipelines and valves to form a closed-loop automated filtration system.

[0025] Specifically, the pre-coating tank 1 is mainly used for preparing and temporarily storing slurry containing filter aid. The agitator 2 is fixedly installed on the top of the pre-coating tank 1. The agitator 2 includes a drive motor and an agitator blade extending to the bottom inside the pre-coating tank 1. The drive motor drives the agitator blade to rotate continuously to mechanically stir the filter aid slurry in the pre-coating tank 1, keeping the slurry in a uniform suspension state and preventing solid particles from settling.

[0026] The candle filter 3 is the core separation device of this apparatus. It includes a vertically arranged cylinder 4, a perforated plate 6 fixedly connected to the upper part of the cylinder 4, and several filter candles 5 suspended on the perforated plate 6. The outer edge of the perforated plate 6 is sealed and welded to the inner wall of the cylinder 4 or fixedly connected by a flange, thereby dividing the inner cavity of the cylinder 4 into a clean side chamber located at the top and a filter side chamber located at the bottom. The filter candle 5 has a slender tubular structure, and its top end is fixedly connected to the mounting hole of the perforated plate 6. The tube extends vertically downward into the lower filter side chamber. The internal channel of the filter candle 5 passes through the perforated plate 6 and communicates directly with the upper clean side chamber.

[0027] The lower side wall of the cylinder 4 has a raw liquid inlet 7, which connects to the filter side chamber at the bottom of the cylinder 4 for introducing the turbid liquid to be filtered. The top end cap of the cylinder 4 has a clear liquid outlet 8, which connects to the clean side chamber at the top of the cylinder 4 for discharging the filtered clear liquid. All parts of the cylinder 4, filter candle 5, and bag-type security filter 9 mentioned later that come into contact with liquid are made of corrosion-resistant materials to meet the corrosive requirements of the high salinity and organic environment in the epichlorohydrin production process.

[0028] In terms of fluid transport, the input end of the pre-coating pump 11 is connected to the outlet of the pre-coating tank 1 through a pipeline, and the output end of the pre-coating pump 11 is connected to the raw liquid inlet 7 of the candle filter 3 through a pipeline. It is used to pump the uniformly mixed lignocellulose slurry into the cylinder 4 to establish a pre-coating layer on the surface of the filter candle 5. The output end of the feed pump 10 is also connected to the raw liquid inlet 7 through a pipeline. It is used to transport the epichlorohydrin process brine to be treated to the filtration system. Flow path switching valves are installed on the connecting pipelines between the raw liquid inlet 7 and the pre-coating pump 11, as well as between the raw liquid inlet 7 and the feed pump 10. The pre-coating mode and the normal feed filtration mode are switched by the opening and closing state of the flow path switching valves.

[0029] The bag filter 9 is connected in series on the pipeline at the rear end of the clean liquid outlet 8. The inlet of the bag filter 9 and the clean liquid outlet 8 are fixedly connected through the pipeline. The outlet of the bag filter 9 serves as the final clean liquid output end of the entire device. The bag filter 9 is equipped with a support basket and a filter bag located inside the support basket to intercept trace impurities that may penetrate the candle filter 3, forming a dual-stage filtration guarantee.

[0030] To achieve online regeneration of the filter element, the device is also equipped with a backflushing and slag discharge system. The compressed gas source 12 is connected to the air inlet of the backflushing valve 13 through a pipeline. The air outlet of the backflushing valve 13 is connected to the connecting pipeline between the clear liquid outlet 8 and the bag security filter 9. An air storage tank is also provided between the compressed gas source 12 and the backflushing valve 13 to store high-pressure gas and release pulse airflow during backflushing. The slag discharge valve 14 is fixedly installed at the bottom of the cylinder 4. The bottom of the cylinder 4 is designed with a conical structure. The slag discharge valve 14 is located at the lowest point of the conical structure, which facilitates the collection and discharge of mixed waste residue containing salt, impurities and lignocellulose under the action of gravity.

[0031] The device also includes a control cabinet 15, which integrates a PLC controller. The control cabinet 15 is electrically connected to the agitator 2, feed pump 10, pre-coating pump 11, backflush valve 13, slag discharge valve 14, and various flow path switching valves via cables. It is used to automatically regulate the start-up, shutdown, opening and closing of each component according to a preset differential pressure signal or time program, so as to realize unattended operation of the device. To address the technical problems of unstable control of epichlorohydrin brine filtration accuracy and susceptibility to contamination in subsequent processes in the prior art, the candle filter 3, as the main filtration equipment, adopts a specific internal component combination design. Furthermore, the candle filter 3 and the bag security filter 9 at the rear end form a precise cascade filtration relationship.

[0032] Please refer to the following carefully. Figure 3 The core structure of the candle filter 3 is described in detail below. The filter candle 5 is the key component for achieving precision filtration. It is a hollow, elongated tubular structure, and one or more layers of precision metal mesh are tightly wrapped around its outer surface. This metal mesh has a micron-sized pore size, serving as both a basic barrier to intercept impurities and a framework for the subsequent attachment of filter aids. The tube sheet 6 is horizontally fixed to the upper part of the inner wall of the cylinder 4. The tube sheet 6 has several mounting holes. The top end of each filter candle 5 is sealed and fixed in the mounting holes of the tube sheet 6 by threaded connection or flange clamping, so that the filter candle 5 is vertically suspended in the space below the cylinder 4. This suspended installation structure, combined with the sealing and separating effect of the tube sheet 6, forces all liquid entering from the raw liquid inlet 7 to penetrate the tube wall of the filter candle 5 from the outside to the inside before entering the space above the tube sheet 6, thereby eliminating the possibility of liquid short circuit.

[0033] Based on this structure, the effectiveness of the pre-coating process is guaranteed at the physical level. When the pre-coating pump 11 is started, the lignocellulose slurry in the pre-coating tank 1 is pumped into the lower chamber of the cylinder 4. Driven by the pressure difference, the liquid passes through the metal mesh and enters the internal cavity of the filter candle 5. The lignocellulose fibers are intercepted by the metal mesh and stacked layer by layer on the outer surface of the filter candle 5 to form a pre-coating layer with uniform thickness and dense structure. This pre-coating layer actually constitutes the highest precision filter medium, which can effectively adsorb colloids and fine particles in the brine, ensuring the high cleanliness requirements of the epichlorohydrin process brine.

[0034] Meanwhile, to further improve system reliability, please refer to... Figure 4 The bag filter 9 complements the candle filter 3 in structure. Inside the housing of the bag filter 9, there is a metal support basket. A microporous filter bag is fitted inside the support basket. The edge of the filter bag opening is sealed to the inlet structure of the bag filter 9 by a pressure ring. This inner basket design can withstand the impact of high-flow liquid and prevent the filter bag from being damaged or deformed during operation. In the assembled state, the clear liquid treated by the candle filter 3 directly enters the filter bag of the bag filter 9. If the pre-coating of the candle filter 3 is slightly peeled off or momentary permeation occurs due to pressure fluctuations, these escaped fine particles will be completely intercepted by the filter bag. This cascaded structure ensures the absolute cleanliness of the final output liquid and completely eliminates the risk of clogging of the downstream ion exchange membrane or electrolyzer.

[0035] For the power source setting that drives the fluid to flow between the above components, those skilled in the art can select a centrifugal pump or a magnetic pump as the feed pump 10 and the pre-coating pump 11 according to the head and flow requirements of the actual working conditions, and accurately control the filtration flow rate by adjusting the pump speed or the opening of the outlet valve. With the aforementioned fixed connection structure, the stability and continuity of the overall filtration process can be ensured.

[0036] Based on the above embodiments, the present invention may further include the following preferred technical solutions: As a preferred embodiment, in order to improve the thoroughness and efficiency of filter cake detachment during the backflushing slag discharge stage, a gas storage tank is fixedly connected in series on the connecting pipeline between the compressed gas source 12 and the backflushing valve 13. The gas storage tank is used to pre-accumulate high-pressure gas. When the backflushing valve 13 is opened, the gas accumulated in the gas storage tank can be released rapidly in the form of a pulse, forming a reverse airflow with instantaneous high impact force. This reverse airflow rushes into the interior of the cylinder 4 through the clear liquid outlet 8 and enters the inner cavity of the filter candle 5, forcing the metal mesh wrapped around the filter candle 5 to expand outward instantly, causing the filter cake layer attached to the surface of the metal mesh to crack and break off, effectively avoiding the situation where the filter cake softens or sticks and cannot be detached due to the slow rise of backflushing pressure.

[0037] As another preferred embodiment, in order to achieve precise switching and isolation of each process flow, electric shut-off valves or pneumatic ball valves are respectively installed on the connecting pipeline between the raw liquid inlet 7 and the pre-coating pump 11, and on the connecting pipeline between the raw liquid inlet 7 and the feed pump 10. Each shut-off valve is electrically connected to the control cabinet 15 through a signal line. By sending a switching command through the control cabinet 15, it can be ensured that the pipeline where the feed pump 10 is located is in a completely closed state during the pre-coating stage, and the pipeline where the pre-coating pump 11 is located is in a completely closed state during the normal filtration stage, to prevent cross-flow or backflow of fluids of different properties and to ensure the purity of a single flow path.

[0038] To meet the automation requirements of the device, the PLC controller integrated inside the control cabinet 15 is configured as the core logic processing unit. The output ports of the PLC controller are connected to the frequency converter of the agitator 2, the start / stop contactors of the feed pump 10 and the pre-coating pump 11, and the electromagnetic drive coils of the backflush valve 13 and the slag discharge valve 14. The PLC controller has a preset automatic control program based on time parameters or differential pressure sensor feedback signals, which can coordinate the various execution components to perform actions in a predetermined sequence of pre-coating, settling, filtering, liquid discharge, backflush, and slag discharge without frequent manual intervention.

[0039] Meanwhile, considering the potentially strong corrosiveness of the brine medium in epichlorohydrin production, components that come into direct contact with the liquid, such as the shells of the cylinder 4, tube sheet 6, filter candle 5, and bag-type security filter 9, are preferably made of titanium or duplex stainless steel. The conical structure design at the bottom of the cylinder 4, combined with the slag discharge valve 14 installed at the lowest point of the cone, ensures that the stripped solid waste and high-concentration slurry can smoothly slide down and be discharged from the machine under gravity, avoiding dead corners and residual material accumulation at the bottom of the cylinder 4.

[0040] The working principle of the brine filtration device for epichlorohydrin production process provided by this utility model is as follows: At the start of the operation, the pre-coating process is carried out. The filter aid slurry is prepared in the pre-coating tank 1, and the agitator 2 runs continuously to maintain the uniformity of the slurry. The control cabinet 15 issues a command to start the pre-coating pump 11, which pumps the lignocellulose slurry in the pre-coating tank 1 into the raw liquid inlet 7 of the candle filter 3 through the pipeline. The slurry enters the inside of the cylinder 4 and contacts the outer surface of the filter candle 5. Under pressure, the liquid in the slurry passes through the filter candle 5 and enters the upper chamber, while the lignocellulose particles are trapped on the metal mesh on the surface of the filter candle 5, gradually accumulating to form a uniform and dense pre-coating layer. This pre-coating layer lays a solid foundation for the subsequent high-precision filtration operation.

[0041] After the pre-coating is completed, the flow path switching valve is used to switch to the feeding mode and the feed pump 10 is started. The epichlorohydrin process brine to be filtered enters the lower part of the cylinder 4 from the raw liquid inlet 7. Under pressure, the brine passes through the pre-coating on the outside of the filter candle 5 and the metal mesh of the filter candle 5 body in sequence. Impurities are intercepted by the pre-coating. The clarified liquid passes through the tube sheet 6 to reach the upper clean side chamber and flows out through the clear liquid outlet 8. Then it enters the series-connected bag security filter 9. The bag security filter 9 performs secondary interception of the liquid. Even if a small amount of impurities pass through the candle filter 3, they will be intercepted by the filter bag in the bag security filter 9, thereby ensuring the cleanliness of the liquid that finally enters the subsequent process.

[0042] As the filtration process continues, the filter cake layer on the surface of the filter candle 5 gradually thickens, causing the inlet and outlet pressure difference to reach the set threshold. The device then enters the backflushing and slag discharge stage. The control cabinet 15 controls the feed pump 10 to stop running and closes the feed passage. Then, the backflushing valve 13 is opened, and the high-pressure gas released by the compressed gas source 12 is reversed into the interior of the candle filter 3 through the clear liquid outlet 8. The gas expands rapidly and impacts outward from the interior of the filter candle 5, causing the filter cake adsorbed on the outer surface of the filter candle 5 to break off and settle to the bottom of the cylinder 4. Subsequently, the slag discharge valve 14 located at the bottom of the cylinder 4 is opened, and the mixed waste residue containing salt, impurities, and lignocellulose is discharged from the slag discharge valve 14. After the regeneration operation is completed, the device can re-enter the pre-coating stage for the next cycle of filtration. All structures cooperate with each other under the coordination of the control cabinet 15 to achieve stable and efficient operation of the filtration process.

[0043] The above are merely specific embodiments of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A brine filtration device for epichlorohydrin production process, characterized in that, Includes a pre-coating tank (1), a mixer (2), a candle filter (3), a bag security filter (9), a feed pump (10), a pre-coating pump (11), a compressed gas source (12), a backflush valve (13), a slag discharge valve (14), and a control cabinet (15). The stirrer (2) is mounted on the pre-coating tank (1). The candle filter (3) includes a cylinder (4), a perforated plate (6) that divides the inner cavity of the cylinder (4) into an upper chamber and a lower chamber, and a filter candle (5) suspended from the perforated plate (6) and extending into the lower chamber. The cylinder (4) is provided with a raw liquid inlet (7) communicating with the lower chamber and a clear liquid outlet (8) communicating with the upper chamber. The input end of the pre-coating pump (11) is connected to the pre-coating tank (1), and the output end is connected to the raw liquid inlet (7). The output end of the feed pump (10) is connected to the raw liquid inlet (7), the inlet of the bag security filter (9) is connected to the clear liquid outlet (8), the compressed gas source (12) is connected to the pipeline where the clear liquid outlet (8) is located via the backflush valve (13), the slag discharge valve (14) is located at the bottom of the cylinder (4), and the control cabinet (15) is electrically connected to the agitator (2), the feed pump (10), the pre-coating pump (11), the backflush valve (13) and the slag discharge valve (14) respectively.

2. A brine filtration device for epichlorohydrin production process according to claim 1, characterized in that, The filter candle (5) has a tubular structure and its outer surface is covered with a metal mesh. The internal channel of the filter candle (5) passes through the flower plate (6) and communicates with the upper chamber.

3. A brine filtration device for epichlorohydrin production process according to claim 1, characterized in that, The bag-type security filter (9) is provided with a support basket and a filter bag located inside the support basket. The outlet of the bag-type security filter (9) constitutes the clean liquid output end of the device.

4. A brine filtration device for epichlorohydrin production process according to claim 1, characterized in that, The agitator (2) includes a drive motor and an agitator blade extending into the pre-coating tank (1), the agitator blade being used to agitate the filter aid slurry in the pre-coating tank (1).

5. A brine filtration device for epichlorohydrin production process according to claim 1, characterized in that, A gas storage tank is provided between the compressed gas source (12) and the backflush valve (13). When the backflush valve (13) is opened, the gas in the gas storage tank enters the filter candle (5) in reverse through the clear liquid outlet (8) to peel off the filter cake.

6. A brine filtration device for epichlorohydrin production process according to claim 1, characterized in that, A flow path switching valve is provided between the raw liquid inlet (7) and the feed pump (10), and between the raw liquid inlet (7) and the pre-coating pump (11). The flow path switching valve is electrically connected to the control cabinet (15).

7. A brine filtration device for epichlorohydrin production process according to claim 1, characterized in that, The bottom of the cylinder (4) is conical, and the slag discharge valve (14) is located at the lowest point of the conical structure, used to discharge mixed waste residue containing salt, impurities and lignocellulose.

8. A brine filtration device for epichlorohydrin production process according to claim 1, characterized in that, The control cabinet (15) integrates a PLC controller, which is configured to control the pre-coating pump (11) to run the pre-coating process, control the feed pump (10) to run the filtration process, and control the backflushing valve (13) and the slag discharge valve (14) to run the backflushing and slag discharge process according to a preset timing sequence.

9. A brine filtration device for epichlorohydrin production process according to claim 1, characterized in that, The liquid-contacting parts of the cylinder (4), filter candle (5) and bag security filter (9) are all made of corrosion-resistant materials.

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