A solid-liquid purification device for chemical waste and a method of using the same

Abstract

The present application relates to a kind of chemical waste solid-liquid purification device and its use method, belong to chemical waste liquid processing equipment technical field;Device includes sequentially communicating primary separation cavity, secondary filter cavity, precision purification cavity along waste liquid flow direction;The primary separation cavity, secondary filter cavity, precision purification cavity three-stage cavity grading collaborative purification: primary separation cavity is strengthened by gradually changing pitch helical guide vane centrifugal separation, remove large particle solid phase in waste liquid;Secondary filter cavity is by synchronous transverse scraper once scraping each level filter screen retained flocculation, gradually intercept intermediate particle size suspended solids;Precision purification cavity is by pulse water flow reverse flushing hollow fiber membrane wire, stripping membrane colloidal contaminant, three stages cooperate to realize long-period continuous purification.Method includes coarse particle cyclone classification, multistage synchronous self-cleaning gradient filtration, hollow fiber membrane precision purification, differential pressure triggers pulse backflushing, adapt to control each unit start-stop, adapt continuous chemical waste liquid processing condition.

Description

Technical Field

[0001] This invention relates to a solid-liquid purification device for chemical waste and its usage method, belonging to the technical field of chemical waste liquid treatment equipment. Background Technology

[0002] Chemical production processes generate large amounts of chemical waste liquid containing coarse particles, fine flocs, and colloidal suspensions. Direct discharge of such waste liquid would cause serious water pollution. Existing graded purification equipment generally adopts a single-stage separation or two-stage combined purification structure, which has obvious shortcomings.

[0003] Traditional hydrocyclones often employ a constant pitch flow guide structure, resulting in poor centrifugal stratification and incomplete separation of coarse particles. A large amount of fine solids directly enters the downstream filtration unit, easily causing rapid clogging of the filter screen and hollow fiber membrane. Multi-stage gradient filtration devices typically have independent cleaning drive mechanisms for each filter stage, leading to numerous components, complex control logic, and a high failure rate. Some integrated scraper structures can only scrape slag in one direction, with the scraping direction aligned with the water flow, making it easy for solids to re-adhere to the screen surface with the water flow, resulting in poor self-cleaning. For example, Chinese Patent Publication No. CN221940155U discloses a solid-liquid separation device for industrial wastewater treatment, including a treatment tank and a cleaning mechanism. The treatment tank contains a horizontal plate with several sieve holes and a feed inlet. The cleaning mechanism includes a cleaning section, a neutralization section, a feed pipe, and a solid crushing box. The cleaning section is rotatably mounted on the horizontal plate and used to sweep solid waste into the feed inlet, which suffers from the aforementioned problems. The existing two-stage cyclone + membrane treatment system lacks an intermediate gradient filtration buffer stage. Fine flocs that are not trapped by the cyclone directly impact the hollow fiber membrane, resulting in a rapid membrane fouling rate, high backwashing frequency, large material consumption, and high operating costs. Conventional membrane cleaning only uses constant water flow rinsing without pulsed water flow impact, making it difficult to remove colloids trapped in the membrane pores, thus limiting the cleaning effect. At the same time, it lacks full-process automated linkage control, with each unit starting and stopping independently, and cannot adaptively adjust the dosing, sludge scraping, and backwashing actions according to the solid content of the waste liquid and the membrane pressure difference.

[0004] Currently, there is a lack of a chemical waste purification device that can achieve integrated linkage of three stages: coarse particle cyclone pre-separation, multi-stage synchronous self-cleaning gradient filtration, and pulse backwash membrane deep purification. It cannot meet the treatment requirements of continuous and stable operation, low clogging rate, and low operation and maintenance cost. Summary of the Invention

[0005] The purpose of this invention is to provide a chemical waste solid-liquid purification device and its usage method. Through the integrated series and coordinated purification of three-section chambers, combined with a gradually variable pitch swirl structure, a synchronous integrated transverse scraping mechanism, and a pulse backwashing membrane assembly, the solid phase load of the waste liquid is reduced step by step, which significantly reduces the probability of filter screen and hollow fiber membrane clogging, simplifies the drive structure, realizes full-process automated linkage control, and extends the continuous operation cycle of the equipment.

[0006] The present invention discloses a chemical waste solid-liquid purification device, comprising a primary separation chamber, a secondary filtration chamber, and a precision purification chamber connected sequentially along the waste liquid flow direction;

[0007] The primary separation chamber is equipped with a cyclone separation mechanism, which includes a cyclone cylinder and a spiral guide plate disposed inside the cyclone cylinder. The pitch of the spiral guide plate gradually decreases along the downward flow direction of the waste liquid. A waste inlet is opened on the side wall of the cyclone cylinder, a heavy phase outlet is provided at the bottom, and a light phase outlet is provided at the top.

[0008] The secondary filtration chamber is equipped with a multi-stage gradient filtration mechanism and an integrated synchronous self-cleaning component. The multi-stage gradient filtration mechanism includes multi-stage filter screens with progressively smaller pore sizes along the waste liquid flow direction. The integrated synchronous self-cleaning component includes multiple cleaning scrapers, a single cleaning drive mechanism, and a solid collection tank. The multiple cleaning scrapers are arranged and fixed to the same mounting frame, corresponding to each filter screen. The cleaning drive mechanism drives the mounting frame to move all the cleaning scrapers synchronously back and forth, with the direction of movement of the cleaning scrapers perpendicular to the waste liquid flow direction. An independent solid collection tank is provided below each filter screen, and a slag discharge port is opened at the bottom of the solid collection tank.

[0009] The precision purification chamber is equipped with a membrane separation component and a pulse backwashing component; the membrane separation component includes hollow fiber membrane filaments; the pulse backwashing component includes a backwashing pipeline, a backwashing pump, and a pulse generator, with the pulse generator located on the backwashing pipeline for outputting pulsed cleaning water flow;

[0010] The light phase outlet of the primary separation chamber is connected to the inlet of the secondary filtration chamber via a first connecting pipe, and the outlet of the secondary filtration chamber is connected to the inlet of the precision purification chamber via a second connecting pipe; the first connecting pipe is equipped with a first control valve, and the second connecting pipe is equipped with a second control valve;

[0011] The primary separation chamber, secondary filtration chamber, and precision purification chamber are three-stage synergistic purification systems: the primary separation chamber enhances centrifugal separation through a gradually pitched spiral guide plate, removing large solid particles from the waste liquid and reducing the load on downstream filtration; the secondary filtration chamber uses a synchronous transverse scraper to remove flocs trapped by each stage of the filter screen in one go, progressively trapping intermediate-sized suspended solids and preventing fine flocs from entering the membrane module; the precision purification chamber uses pulsed water flow to backwash the hollow fiber membrane filaments, stripping colloidal pollutants from the membrane. The three stages work together to achieve long-cycle continuous purification, reducing the frequency of filter and membrane module clogging.

[0012] A three-stage gradient purification system of "coarse removal, intermediate interception, and fine filtration" is constructed, with clear division of labor and reasonable load at each stage. The primary separation chamber is responsible for the removal of large solid particles, significantly reducing the load on downstream filtration. The secondary filtration chamber intercepts intermediate-sized suspended solids step by step, preventing fine flocs from entering the membrane module and effectively protecting the membrane separation unit. The precision purification chamber focuses on deep purification. The three stages work together to enable the entire system to operate continuously for long periods, avoiding overload and clogging of any single filtration unit.

[0013] The gradually increasing pitch structure causes the flow velocity and centrifugal force to increase progressively as the waste liquid spirals down the cylinder wall, achieving stepwise sedimentation and separation of particles with different densities / sizes, which significantly improves the separation accuracy compared to the equal pitch structure. At the same time, the waste liquid generates strong turbulence during the swirling process, which is beneficial for the rapid and uniform mixing of the flocculant and the waste liquid.

[0014] Multi-stage gradient filters achieve particle size classification and interception, with each stage of the filter trapping particles within a specific size range, preventing a single filter from bearing the entire interception load and clogging prematurely. All scrapers are fixed to the same mounting frame and driven synchronously by a single drive mechanism, resulting in a simplified structure, low cost, and high synchronization, allowing for simultaneous cleaning of each stage of the filter in a single operation. The scraper movement direction is perpendicular to the waste liquid flow direction, and the scraped solid particles fall into the collection tank below under gravity, preventing them from being laterally drawn into the filtered purified liquid and causing secondary pollution. The entire cleaning process does not require machine shutdown and does not affect normal filtration operations.

[0015] Solid particles trapped by each stage of the filter fall into their respective collection tanks, achieving graded collection and classified discharge, which facilitates the subsequent classification, recycling, or targeted disposal of solid waste.

[0016] Hollow fiber membrane fibers provide high-precision physical retention, with suspended solids in the effluent as low as 5 mg / L; pulsed backwashing generates high-frequency shock waves and vibration effects, which can effectively remove colloidal pollutants attached to the surface and pores of the membrane fibers, and the membrane flux recovery rate can reach more than 95%, which is significantly improved compared with conventional constant flow backwashing; the three stages work together to achieve a complete purification closed loop of "graded retention + synchronous scraping + pulse regeneration", which greatly reduces the frequency of manual disassembly and cleaning and extends the service life of the membrane module.

[0017] Preferably, the primary separation chamber is also equipped with a flocculant addition mechanism; the flocculant addition mechanism includes a flocculant storage tank, a metering pump, and a dosing ring pipe arranged around the inner wall of the cyclone cylinder, with dosing holes evenly distributed in the dosing ring pipe.

[0018] The flocculant is released evenly at multiple points along the inner wall of the cyclone separator. The high-speed spiral flow of the waste liquid during the cyclone separation process achieves instant and thorough mixing and dispersion, eliminating the need for additional mixing equipment. The structure is compact and the mixing efficiency is extremely high.

[0019] Preferably, the multi-stage filter screen includes a first filter screen, a second filter screen, and a third filter screen arranged sequentially along the waste liquid flow direction; the first filter screen has a pore size of 0.5-2mm, the second filter screen has a pore size of 0.1-0.5mm, and the third filter screen has a pore size of 0.01-0.1mm.

[0020] A complete particle size classification and interception chain is constructed: the first stage intercepts coarse particles (protecting the subsequent fine pore filter), the second stage intercepts medium-sized suspended solids, and the third stage intercepts fine flocs (protecting the downstream membrane module). The load of each filter is balanced, with no single-stage overload. The pore size parameters are optimized and matched to ensure that the particles intercepted in the previous stage will not penetrate into the next stage and cause blockage, while maximizing the overall filtration flux. It effectively controls the suspended particle size entering the precision purification chamber within the range that the membrane module can tolerate, significantly slowing down the membrane fouling rate.

[0021] Preferably, the cleaning drive mechanism is an electric push rod or a hydraulic cylinder, and the gap between the cleaning scraper and the corresponding filter screen surface is controlled to be 0.5-2mm.

[0022] If the gap is too small (<0.5mm), it can easily scratch the filter screen surface or even cause the filter screen to break; if the gap is too large (>2mm), the scraping will not be thorough, and the trapped solid phase will accumulate. A precise gap range of 0.5-2mm ensures effective scraping and trapping of the solid phase while maximizing the protection of the filter screen structure integrity and filtration accuracy; the precise gap, combined with the lateral shearing motion of the scraper, generates a uniform scraping force on the filter screen surface, resulting in high cleaning efficiency without damaging the filter media.

[0023] Preferably, an aeration mechanism is provided inside the precision purification chamber below the membrane separation component. The aeration mechanism includes an aeration pipeline and a microporous aeration disc.

[0024] The microporous aeration disc generates a large number of microbubbles, which, during their ascent, create a continuous gas-liquid two-phase flow that washes over the surface of the hollow fiber membrane filaments. This effectively inhibits the adhesion and deposition of colloidal particles and microorganisms on the membrane filament surface, slows down the rate of membrane fouling, and extends the membrane filtration cycle. Aeration continuously slows down membrane fouling during the normal filtration phase, while pulse backwashing performs powerful regeneration when membrane fouling reaches a certain level. The two processes complement each other on a timescale—aeration provides "routine maintenance," while backwashing provides "periodic deep cleaning"—to jointly extend the service life of the membrane module and reduce replacement frequency and operating costs.

[0025] Preferably, a PLC control system is also configured; the PLC control system is electrically connected to the first control valve, the second control valve, the cleaning drive mechanism, the backwash pump, the pulse generator, the metering pump, and the aeration mechanism respectively, so as to realize the linkage control of the actions of each unit.

[0026] The system achieves fully automated operation, with each process (cyclone separation → flocculation and dosing → multi-stage filtration → scraper cleaning → membrane separation → aeration and flushing → pulse backwashing) automatically switching according to a preset program, requiring no manual intervention. Each unit's actions can be coordinated and linked; for example, the second control valve automatically closes, the backwash pump and pulse generator start when the backwashing program begins, and the filtration state automatically returns to normal after the program ends, with precise and reliable timing. Operating parameters (cleaning cycle, backwash pressure differential threshold, dosing amount, etc.) can be flexibly adjusted according to different waste liquid characteristics, demonstrating strong adaptability. This significantly reduces labor costs and the risk of operational errors.

[0027] Preferably, the cyclone separation mechanism further includes a variable frequency rotary drive assembly; the variable frequency rotary drive assembly includes a drive shaft, a variable frequency motor, and a frequency converter; the spiral guide plate is fixedly installed on the drive shaft, the drive shaft extends upward out of the top of the cyclone cylinder and is connected to the output shaft of the variable frequency motor; the frequency converter is electrically connected to the PLC control system, and the PLC regulates the speed of the variable frequency motor through the frequency converter to achieve stepless adjustment of the spiral guide plate rotation speed from 0-1500 r / min.

[0028] The active rotation of the spiral guide plate generates a forced centrifugal force field, ensuring stable and controllable separation performance unaffected by fluctuations in feed conditions. The steplessly adjustable speed gives the device exceptional adaptability—increasing the speed to enhance centrifugal force when processing high-solids-content or high-density waste liquids, and decreasing the speed to save energy when processing low-solids-content waste liquids. The centrifugal force generated by active rotation is significantly greater than that of passive cyclone separation, greatly improving the sedimentation and separation efficiency of fine particles and broadening the applicability of cyclone separation. A PLC and frequency converter enable precise closed-loop speed control, automatically adjusting the optimal speed in real time based on online detection signals (such as solids content and flow rate), achieving a dynamic balance between separation accuracy and energy consumption.

[0029] Preferably, the PLC control system incorporates a piecewise linear control model for solid content and guide vane rotation speed, calculating the target rotation speed n of the spiral guide vane in three segments based on the solid concentration C of the waste liquid measured by the online solid content detector:

[0030] When 0 < C ≤ 1%, n = 100 + 40000C;

[0031] When 1% < C ≤ 5%, n = 500 + 75(100C − 1);

[0032] When 5% < C ≤ 10%, n = 800 + 140(100C − 5);

[0033] The PLC performs a limiting process on the calculated rotational speed to keep it stable within the range of 100 r / min to 1500 r / min.

[0034] It ensures that the rotation speed is always within the safe operating range of the equipment, while avoiding separation failure due to excessively low rotation speed or equipment overload and energy waste due to excessively high rotation speed; it realizes fully automatic intelligent closed-loop control of "detection-calculation-execution-feedback", which does not require manual experience judgment, and has high control accuracy, fast response and strong adaptability.

[0035] The method of using the chemical waste solid-liquid purification device of the present invention includes the following steps:

[0036] S1. Coarse particle cyclone classification and separation: Chemical waste liquid is fed into the cyclone cylinder from the waste inlet. The waste liquid spirals down along the gradually changing pitch spiral guide plate. Under the action of centrifugal force, the high specific gravity solid particles adhere to the cylinder wall and settle to the bottom and are discharged from the heavy phase outlet; the low specific gravity liquid phase and fine suspended solids flow out from the top light phase outlet.

[0037] S2. Multi-stage synchronous self-cleaning gradient filtration: After primary separation, the waste liquid enters the secondary filtration chamber and passes through a multi-stage filter screen with decreasing pore size to intercept intermediate particle size flocs; the cleaning drive mechanism drives the overall mounting frame to move laterally back and forth at timed intervals, and the cleaning scraper simultaneously scrapes off the solid phase intercepted on the surface of each stage of the filter screen. The solid phase falls into the solid collection tank below and is discharged through the slag discharge port.

[0038] S3. Hollow fiber membrane precision purification: After secondary filtration and buffering, the waste liquid enters the precision purification chamber and passes through the hollow fiber membrane to complete the deep interception of colloids and trace suspended solids. The purified liquid is discharged from the outlet of the precision purification chamber.

[0039] S4. Differential Pressure Triggered Pulse Backwash: Real-time monitoring of the filtration differential pressure on both sides of the membrane module. When the differential pressure reaches the preset threshold, the backwash pump and pulse generator are started. The pulse water flow flows outward from the inside of the hollow fiber membrane to flush away colloidal pollutants trapped in the membrane pores, thus completing membrane regeneration.

[0040] Utilizing centrifugal force, this system achieves highly efficient pre-removal of large solid particles, resulting in a high removal rate and significantly reducing the solid load on subsequent filtration units. The gradually increasing screw pitch design enhances the separation process at each stage, achieving superior separation accuracy compared to conventional constant-pitch hydrocyclones. Multi-stage gradient filtration effectively traps intermediate-sized suspended solids, ensuring balanced load and preventing clogging at each filter level. Simultaneous scraping cleans all filters in a single operation, offering high efficiency and short processing time without disrupting continuous filtration. Scraped solids are collected in a lower collection tank for centralized discharge, facilitating classified disposal or recycling. This results in high-quality purified effluent with suspended solids content ≤5mg / L, meeting the standards for chemical wastewater discharge or reuse. Using filtration pressure difference as a quantitative indicator of membrane fouling, backwashing is initiated at the appropriate time to avoid wasting energy by backwashing too early and causing irreversible fouling by backwashing too late. The pulsed water flow generates shock waves and vibration effects, resulting in better membrane flux recovery than conventional constant flow backwashing. The entire process achieves a complete closed-loop continuous operation from feeding → classification → filtration → deep purification → online regeneration, without the need for shutdown cleaning, resulting in high treatment efficiency and low operating costs.

[0041] Preferably, in step S1, flocculant is added simultaneously, and the amount of flocculant added is 0.01%-0.1% of the waste liquid volume;

[0042] In step S2, the cleaning scraper performs a complete scraping cycle every 5-30 minutes.

[0043] The preset threshold for differential pressure in step S4 is 1.5-2.0 times the initial operating differential pressure; the pulse backwashing frequency is 1-10Hz, and the duration of a single pulse is 1-5s.

[0044] The optimized addition range, verified through optimization, ensures that fine suspended solids are fully flocculated into larger flocs (facilitating subsequent filtration and retention) without increasing chemical sludge production and reagent costs due to excessive addition. For high solids content, the interval is shortened to 5 minutes per cycle (preventing rapid filter clogging), while for low solids content, it can be extended to 30 minutes per cycle (reducing unnecessary wear and energy consumption), achieving optimal matching between cleaning frequency and treatment conditions. A 1.5 times threshold is suitable for conditions with weak contaminant adhesion and slow flux decline (pre-rinsing, lower energy consumption); a 2.0 times threshold is suitable for conditions with strong contaminant adhesion and where reducing backwashing frequency is desired. This range ensures timely regeneration before membrane fouling reaches an irreversible stage, protecting the membrane module and avoiding excessive backwashing. Low-frequency (1-3Hz) pulses have strong impact force and are suitable for situations with strong contaminant adhesion; high-frequency (5-10Hz) pulses have a high frequency and are suitable for rapid removal of fine particulate contaminants. The 1-10Hz range covers the stripping requirements of most chemical waste liquid membrane pollutants; the single pulse duration of 1-5s, combined with the pulse frequency, ensures that each pulse has sufficient impact time while preventing fatigue damage to the membrane fibers caused by excessive continuous impact; this parameter combination has been optimized and verified to achieve the best membrane flux recovery effect in the shortest backwash time, reducing backwash fluid consumption and energy consumption.

[0045] The volume ratio P (in %) of flocculant addition can be synchronized with the solid content:

[0046] P = 0.01 + 0.9C

[0047] The applicable range is 0 < C ≤ 10%, and the dosage range is 0.01%-0.1%. The PLC can use this formula to synchronously control the output frequency of the metering pump, forming a two-level quantitative linkage of "solid content → speed → dosage".

[0048] Compared with the prior art, the present invention has the following significant advantages:

[0049] 1. This invention uses a gradually varying pitch spiral guide plate. The upper part of the cyclone cylinder has a large pitch and a large fluid flow space, which fully disperses the waste liquid. The lower part has a smaller pitch, which narrows the fluid rotation radius and increases the centrifugal force. The efficiency of coarse particle sedimentation and separation is improved compared with a constant pitch cyclone separator, which greatly reduces the amount of large solid particles entering the secondary filtration chamber and reduces the probability of filter screen wear and clogging from the source.

[0050] 2. The secondary filtration chamber adopts a single-drive integrated synchronous transverse scraper structure. One drive mechanism cleans all multi-stage filter screens simultaneously. Compared with the independent drive components of each stage filter screen, this reduces power components, simplifies the equipment structure, and reduces the failure rate. The transverse movement of the scraper is perpendicular to the flow direction of the waste liquid, preventing flocs from adhering to the screen surface again along the water flow. The self-cleaning effect is significantly better than the same-direction scraping structure. The multi-stage gradient pore size filter screen intercepts intermediate flocs step by step, forming a buffer barrier to prevent fine flocs from directly impacting the downstream membrane module.

[0051] 3. It adopts a three-stage integrated collaborative architecture of "cyclone coarse separation → multi-stage synchronous self-cleaning filtration → pulse membrane fine filtration", which is different from the existing two-stage treatment equipment. The two-stage pre-filtration collaboratively share the solid phase load, reduces the amount of pollutants adhering to the surface of the hollow fiber membrane, and extends the membrane pulse backwashing cycle, significantly reducing cleaning water consumption, energy consumption and membrane fiber replacement costs.

[0052] 4. Membrane cleaning is paired with a pulse generator to output intermittent pulse water flow. Compared with constant water flow rinsing, the pulse impact force can deeply remove colloidal impurities in the micropores of the membrane fibers, improving the membrane regeneration effect. With the addition of micropore aeration under the membrane, the surface of the membrane fibers is continuously disturbed, further slowing down the deposition of pollutants.

[0053] 5. The entire process is controlled by PLC linkage, which can adaptively adjust the start and stop of each unit according to the flocculant dosage, filter scraping cycle and membrane pressure difference. No manual segmented operation is required. It is suitable for continuous chemical waste liquid treatment and has a high degree of automation.

[0054] 6. It is equipped with a dedicated treatment process, which limits the flocculant addition ratio, scraper cleaning cycle, differential pressure backwash threshold, and pulse flushing parameters. It matches the three-stage equipment graded load characteristics to form a complete purification process suitable for high solid content chemical waste liquid. The synergistic purification effect of this process cannot be achieved by using cyclone, filtration, or membrane equipment alone. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of the overall structure of a chemical waste solid-liquid purification device according to the present invention;

[0056] Figure 2 This is a schematic diagram of the structure of a primary separation chamber according to the present invention;

[0057] Figure 3 This is a schematic diagram of the structure of a two-stage filtration chamber according to the present invention;

[0058] Figure 4 This is a schematic diagram of the structure of a precision purification chamber according to the present invention.

[0059] In the diagram: 1. Primary separation chamber; 11. Cyclone cylinder; 12. Spiral guide plate; 13. Waste inlet; 14. Heavy phase outlet; 15. Light phase outlet; 16. Flocculant storage tank; 17. Metering pump; 18. Dosing ring pipe;

[0060] 2. Secondary filtration chamber; 21. First filter screen; 22. Second filter screen; 23. Third filter screen; 24. Cleaning scraper; 25. Cleaning drive mechanism; 26. Mounting bracket; 27. Solid collection tank; 28. Slag discharge port;

[0061] 3. Precision purification chamber; 31. Hollow fiber membrane; 32. Backwashing pipeline; 33. Backwashing pump; 34. Pulse generator; 35. Aeration pipeline; 36. Microporous aeration disc; 37. Water outlet;

[0062] 4. First connecting pipe; 41. First control valve; 5. Second connecting pipe; 51. Second control valve. Detailed Implementation

[0063] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0064] Example 1

[0065] like Figure 1 As shown, a chemical waste solid-liquid purification device includes a primary separation chamber 1, a secondary filtration chamber 2, and a precision purification chamber 3 connected sequentially along the waste liquid flow direction.

[0066] (I) Structure of the primary separation chamber

[0067] The primary separation chamber 1 is equipped with a cyclone separation mechanism. For example... Figure 2 As shown, the cyclone separation mechanism includes a cyclone cylinder 11 and a spiral guide plate 12 disposed inside the cyclone cylinder 11. A waste inlet 13 is provided on the upper side wall of the cyclone cylinder 11, which is tangentially arranged along the cyclone cylinder 11 to allow waste liquid to enter the cyclone cylinder 11 tangentially. A heavy phase outlet 14 is provided at the bottom of the cyclone cylinder 11, and a light phase outlet 15 is provided at the top of the cyclone cylinder 11.

[0068] The pitch of the spiral guide plate 12 gradually decreases along the downward flow direction of the waste liquid (i.e., the pitch gradually decreases from top to bottom), so that the flow velocity and centrifugal force of the waste liquid gradually increase during the swirling process, which is beneficial to the classification and sedimentation of particles of different sizes. The spiral guide plate 12 is fixedly installed on the drive shaft, which extends upward out of the top of the swirling cylinder 11 and is connected to the output shaft of the variable frequency motor. The variable frequency motor is equipped with a frequency converter, which is electrically connected to the PLC control system. The PLC control system regulates the speed of the variable frequency motor through the frequency converter, so that the rotation speed of the spiral guide plate 12 is steplessly adjustable within the range of 0-1500 r / min.

[0069] The primary separation chamber 1 is also equipped with a flocculant addition mechanism. The flocculant addition mechanism includes a flocculant storage tank 16, a metering pump 17, and a dosing ring pipe 18 arranged around the inner wall of the cyclone cylinder 11. Dosing holes are evenly distributed on the dosing ring pipe 18. The flocculant storage tank 16 stores polyaluminum chloride (PAC) flocculant. The inlet of the metering pump 17 is connected to the flocculant storage tank 16, and the outlet of the metering pump 17 is connected to the dosing ring pipe 18.

[0070] (II) Structure of the Secondary Filtration Chamber

[0071] like Figure 3 As shown, the secondary filter chamber 2 is equipped with a multi-stage gradient filtration mechanism and an integrated synchronous self-cleaning component.

[0072] The multi-stage gradient filtration mechanism includes multiple filter screens with progressively smaller pore sizes along the waste liquid flow direction. In this embodiment, the multi-stage filter screen specifically includes a first filter screen 21, a second filter screen 22, and a third filter screen 23 arranged sequentially along the waste liquid flow direction. The first filter screen 21 has a pore size of 1 mm, the second filter screen 22 has a pore size of 0.3 mm, and the third filter screen 23 has a pore size of 0.05 mm. Each filter screen is made of stainless steel, which has good corrosion resistance. The three filter screens are arranged sequentially along the waste liquid flow direction, forming a gradient filtration system from coarse to fine.

[0073] The integrated synchronous self-cleaning assembly includes multiple cleaning scrapers 24, a single cleaning drive mechanism 25, and multiple solid collection tanks 27. The multiple cleaning scrapers 24 are arranged one-to-one with each filter screen (i.e., one cleaning scraper 24 corresponds to the first filter screen 21, one cleaning scraper 24 corresponds to the second filter screen 22, and one cleaning scraper 24 corresponds to the third filter screen 23), and each cleaning scraper 24 is fixed to the same mounting bracket 26. The cleaning drive mechanism 25 is an electric push rod (or hydraulic cylinder), which drives the mounting bracket 26 to synchronously reciprocate all the cleaning scrapers 24. The direction of movement of the cleaning scrapers 24 is perpendicular to the direction of waste liquid flow (i.e., lateral reciprocating motion). The gap between the cleaning scraper 24 and the corresponding filter screen surface is controlled at 1mm, which effectively removes trapped solid particles while avoiding damage to the filter screen.

[0074] Each filter screen is equipped with an independent solid collection tank 27 (i.e., one solid collection tank 27 is set below the first filter screen 21, one solid collection tank 27 is set below the second filter screen 22, and one solid collection tank 27 is set below the third filter screen 23). Each solid collection tank 27 has a slag discharge port 28 at its bottom, and a slag discharge valve (not shown in the figure) is provided at the slag discharge port 28.

[0075] (III) Structure of the Precision Purification Chamber

[0076] like Figure 4As shown, the precision purification chamber 3 is equipped with a membrane separation component, a pulse backwashing component, and an aeration mechanism.

[0077] The membrane separation unit includes several hollow fiber membrane filaments 31. The hollow fiber membrane filaments 31 are arranged longitudinally, and the filament material is polyvinylidene fluoride (PVDF) with a molecular weight cutoff of 100 kDa. The two ends of the hollow fiber membrane filaments 31 are fixed to the upper and lower end caps or tube sheets of the membrane shell by resin casting, forming a membrane bundle. The internal channels (tube side) of the membrane filaments are connected to the permeate / backwash inlet and outlet at the top of the precision purification chamber 3, and the external space (shell side) of the membrane filaments is connected to the inlet at the bottom of the precision purification chamber 3.

[0078] The pulse-type backwash assembly includes a backwash line 32, a backwash pump 33, and a pulse generator 34. One end of the backwash line 32 is connected to the product water / backwash inlet / outlet at the top of the precision purification chamber 3, and the other end is connected to the cleaning fluid source. The backwash pump 33 is located at the inlet end of the backwash line 32 (i.e., the end closest to the cleaning fluid source) to provide pressure driving force for backwashing. The pulse generator 34 is located on the backwash line 32, specifically on the section between the backwash pump 33 and the product water / backwash inlet / outlet of the precision purification chamber 3, to apply a pulse action to the water flowing through the line, transforming it into a pulsed cleaning water flow. A second control valve 5 is also provided on the backwash line 32 to control the opening and closing of the backwash line. A check valve 321 (one-way valve) is also connected in series on the backwash line 32 to prevent product water from flowing back into the backwash line during normal filtration.

[0079] The aeration mechanism is located inside the precision purification chamber 3, below the membrane separation assembly. The aeration mechanism includes an aeration pipe 35 and a microporous aeration disc 36. One end of the aeration pipe 35 is connected to an external air source (such as a blower or air compressor), and the other end is connected to the microporous aeration disc 36. The microporous aeration disc 36 is horizontally installed at the bottom of the precision purification chamber 3, directly below the hollow fiber membrane filaments 31. Its surface is densely covered with tiny pores, which can disperse the gas into a large number of microbubbles.

[0080] The bottom of the precision purification chamber 3 is equipped with a water inlet for the waste liquid after secondary filtration to enter the shell side of the precision purification chamber 3. The top of the precision purification chamber 3 is equipped with a water outlet 37 for the purified water to be discharged.

[0081] The light phase outlet 15 of the primary separation chamber 1 is connected to the inlet of the secondary filtration chamber 2 via the first connecting pipe 4 (i.e., the liquid flowing out of the light phase outlet 15 directly enters the secondary filtration chamber 2). The outlet of the secondary filtration chamber 2 is connected to the inlet of the precision purification chamber 3 via the second connecting pipe 5. A first control valve 41 is provided on the first connecting pipe 4, and a second control valve 51 is provided on the second connecting pipe 5, for controlling the opening and closing of the pipeline between the secondary filtration chamber 2 and the precision purification chamber 3.

[0082] The heavy phase outlet 14 of the primary separation chamber 1 is connected to the heavy phase collection container (not shown in the figure) to discharge the separated large solid particles. The slag discharge port 28 of each solid collection tank 27 is connected to the solid phase collection container (not shown in the figure) to discharge the solid particles trapped by the filter screens at each stage.

[0083] The device is also equipped with a PLC control system. The PLC control system is electrically connected to the first control valve 41, the second control valve 51, the cleaning drive mechanism 25, the backwash pump 33, the pulse generator 34, the metering pump 17, the air supply device (such as a blower) of the aeration mechanism, the frequency converter motor, and the online solid content detector, respectively, to realize the linkage control of the actions of each unit.

[0084] The PLC control system incorporates a piecewise linear control model for solid content and guide vane rotation speed. This model calculates the target rotation speed n of the spiral guide vane 12 in three segments based on the solid content concentration C of the waste liquid measured by an online solid content analyzer.

[0085] When 0 < C ≤ 1%, n = 100 + 40000C;

[0086] When 1% < C ≤ 5%, n = 500 + 75(100C − 1);

[0087] When 5% < C ≤ 10%, n = 800 + 140(100C − 5).

[0088] The PLC control system performs amplitude limiting on the calculated rotational speed, keeping the rotational speed stable within the range of 100 r / min to 1500 r / min.

[0089] The working process of the device of this invention can be summarized as "three-stage graded synergistic purification":

[0090] First stage (primary separation chamber): The waste liquid flows downward in a swirling motion under the guidance of a gradually decreasing pitch spiral guide plate, with the centrifugal force gradually increasing as the pitch decreases. Large solid particles are thrown against the cylinder wall and settle out, while the flocculant is uniformly mixed during the swirling process, causing fine suspended matter to flocculate and grow. This stage is responsible for removing coarse particles and pre-treating flocculation, significantly reducing the load on the downstream filtration.

[0091] The second stage (secondary filtration chamber): Waste liquid passes sequentially through three stages of filter screens with decreasing pore sizes. Each stage of the filter screen traps intermediate-sized suspended solids according to particle size classification. Simultaneously, a horizontal scraper removes the flocs trapped on the surface of each stage of the filter screen in one pass, and the scraped solid phase falls into an independent collection tank below for discharge. This stage is responsible for the step-by-step trapping of intermediate-sized suspended solids and online self-cleaning, preventing fine flocs from entering the membrane module.

[0092] The third section (precision purification chamber): Waste liquid passes through hollow fiber membrane fibers to achieve deep retention of colloids and trace suspended solids. The bottom aeration mechanism continuously flushes the membrane fiber surface to delay membrane fouling; when the pressure difference reaches the threshold, the pulse backwashing component is activated, and pulsed water flow flushes from the inside of the membrane fibers outward to remove colloidal pollutants and restore membrane flux. This section is responsible for deep purification and online regeneration.

[0093] The three stages work together to achieve long-term continuous purification, effectively reducing the frequency of clogging of filters and membrane modules, and significantly reducing the frequency of manual intervention and processing costs.

[0094] Example 2

[0095] This embodiment provides a method for using the device described in Embodiment 1 to purify solid and liquid chemical waste, including the following steps:

[0096] S1: Coarse particle cyclone classification separation

[0097] Chemical waste liquid is tangentially fed into the cyclone cylinder 11 through waste inlet 13. Guided by the gradually decreasing pitch spiral guide plate 12, the waste liquid spirals downwards along the inner wall of the cyclone cylinder 11. During the spiral descent, the flow velocity of the waste liquid gradually increases due to the gradually decreasing pitch of the spiral guide plate 12, and the centrifugal force gradually increases. Under the action of centrifugal force, denser solid particles move towards the inner wall of the cyclone cylinder 11 and deposit to the bottom, and are discharged from the heavy phase outlet 14. Less dense liquid and fine suspended matter flow out from the top light phase outlet 15.

[0098] At the same time, the PLC control system calculates the target rotation speed n based on the solid content concentration C of the waste liquid measured by the online solid content detector, and drives the spiral guide plate 12 to rotate actively through the frequency converter to achieve the best cyclone separation effect.

[0099] Simultaneously with step S1, flocculant is added to the waste liquid in the primary separation chamber 1 via a flocculant addition mechanism. Polyaluminum chloride (PAC) is selected as the flocculant, which is precisely metered by metering pump 17 and evenly released into various parts of the inner wall of the cyclone separator 11 through the dosing holes of the dosing ring pipe 18. Utilizing the high-speed spiral flow of the waste liquid during the cyclone separation process, the flocculant mixes thoroughly with the waste liquid, causing the fine suspended matter in the waste liquid to flocculate into larger particles. The amount of flocculant added is 0.05% of the waste liquid volume.

[0100] After step S1, solid particles with a diameter greater than 0.5 mm can be removed, with a removal rate of over 95%.

[0101] S2: Multi-level synchronous self-cleaning gradient filtering

[0102] The waste liquid after primary separation in step S1 enters the secondary filtration chamber 2 directly from the light phase outlet 15. The waste liquid sequentially passes through a multi-stage filter screen with decreasing pore size—first through the first filter screen 21 (1mm pore size), which traps large particles; then through the second filter screen 22 (0.3mm pore size), which traps medium-sized suspended solids; and finally through the third filter screen 23 (0.05mm pore size), which traps fine flocs. Each stage of the filter screen progressively traps intermediate-sized suspended solids and prevents fine flocs from entering the subsequent membrane module.

[0103] Under the control of the PLC control system, the cleaning drive mechanism 25 drives the overall mounting frame 26 to move laterally and reciprocally at regular intervals. The cleaning scraper 24 performs a complete scraping cycle every 15 minutes: all cleaning scrapers 24 move laterally synchronously, scraping away the solid phase trapped on the surface of each filter screen in one go. The scraped solid phase falls into the independent solid collection tank 27 below the corresponding filter screen under gravity and is discharged through the discharge port 28. Each solid collection tank 27 independently collects solid particles of different particle sizes, facilitating subsequent classification and recycling.

[0104] The cleaning scraper 24 moves in a direction perpendicular to the flow of waste liquid. The scraped solid particles fall directly into the collection tank under the action of gravity, and will not be rolled into the filtered purified liquid laterally, causing secondary pollution.

[0105] S3: Hollow fiber membrane precision purification

[0106] After multi-stage filtration and buffering in step S2, the waste liquid is released through the first control valve 41 under the control of the PLC control system. The waste liquid enters the shell side (i.e., the external space of the hollow fiber membrane filament 31) of the precision purification chamber 3 from the bottom inlet of the first connecting pipe 4. Under pressure, the waste liquid passes through the membrane wall of the hollow fiber membrane filament 31 and enters the internal channel (tube side) of the membrane filament, completing the deep interception of colloids and trace suspended solids. The purified liquid (product water) flows out from the product water / backwash inlet and outlet at the top of the precision purification chamber 3 and is finally discharged from the outlet 37.

[0107] During membrane separation, the PLC control system continuously controls the aeration mechanism: an external air source (blower) supplies air, which is delivered to the microporous aeration disc 36 via aeration pipeline 35. The microporous aeration disc 36 generates a large number of microbubbles. These microbubbles rise from below the membrane module, forming intense gas-liquid two-phase turbulence around the hollow fiber membrane filaments 31. This generates continuous scouring and shearing forces on the membrane filament surface, effectively inhibiting the adhesion and deposition of colloidal particles and microorganisms on the membrane filament surface, and slowing down the rate of membrane fouling.

[0108] Tests showed that the suspended solids content in the effluent after this treatment step was less than 5 mg / L, meeting the discharge standards for chemical wastewater.

[0109] S4: Differential pressure triggers pulse backflushing

[0110] During membrane separation, the PLC control system monitors the filtration pressure difference across the membrane module in real time using pressure sensors installed on the shared pipe section for the permeate / backwash inlet and outlet. When the filtration pressure difference reaches a preset threshold (1.8 times the initial operating pressure difference), the PLC control system initiates the backwashing procedure.

[0111] The specific steps of the backwashing procedure are as follows:

[0112] Close the second control valve 51 (cut off the waste liquid supply from the secondary filtration chamber to the precision purification chamber), and close the valve at the outlet 37. Start the backwash pump 33 and pulse generator 34. The cleaning solution (which can be permeate or a special cleaning agent) is pumped into the internal channel (tube side) of the hollow fiber membrane filament 31 through the backwash pipeline 32. At the same time, the pulse generator 34 generates a pulsed water flow with a pulse frequency of 5Hz and a single pulse duration of 3 seconds to perform pulse backwashing on the membrane filament. The total backwashing time is 60 seconds.

[0113] The pulsed water flow flows outward from the internal channels of the hollow fiber membrane filament 31, penetrating the membrane wall to the shell side. The shock waves and vibration effects generated by the pulsed water flow can effectively remove colloidal pollutants attached to the surface of the membrane filaments and inside the membrane pores, restoring membrane flux. The backwash wastewater is discharged from the bottom inlet of the precision purification chamber 3 and collected for treatment (at this time, the second control valve 51 is closed, and the backwash wastewater will not flow back into the secondary filtration chamber 2).

[0114] After backwashing is completed, the PLC control system shuts down the backwash pump 33 and pulse generator 34, closes the second control valve 5, and opens the valves of the first control valve 41 and the outlet 37 to restore normal filtration.

[0115] Example 3

[0116] The difference between this embodiment and Embodiment 2 is as follows:

[0117] The type and amount of flocculant used in step S1 vary. In this embodiment, polyferric sulfate (PFS) is used as the flocculant, and the amount added is 0.02% of the waste liquid volume. For chemical waste containing a large amount of organic pollutants, polyferric sulfate has a better flocculation effect.

[0118] Example 4

[0119] The difference between this embodiment and Embodiment 2 is as follows:

[0120] The cleaning frequency of the cleaning scraper 24 varies in step S2. In this embodiment, the PLC control system automatically adjusts the cleaning frequency according to the solid content of the waste liquid.

[0121] For chemical waste with a high solid content (solid content > 5%), the cleaning scraper 24 performs a complete slag scraping cycle every 5 minutes;

[0122] For chemical waste with low solid content (solid content <1%), the cleaning scraper 24 performs a complete slag scraping cycle every 30 minutes;

[0123] For chemical waste with a general solid content (1%-5%), the cleaning scraper 24 performs a complete scraping cycle every 15 minutes.

[0124] The cleaning frequency can be flexibly adjusted according to the actual working conditions through the PLC control system, achieving the optimal match between the cleaning frequency and the processing conditions, which not only prevents filter clogging but also reduces unnecessary wear and energy consumption.

[0125] Example 5

[0126] The difference between this embodiment and Embodiment 2 is as follows:

[0127] The parameters for pulse backwashing in step S4 are different. In this embodiment, backwashing is initiated when the filtration differential pressure of the membrane separation module reaches 1.5 times the initial differential pressure (earlier than 1.8 times in Example 2), the pulse frequency is 10Hz (higher frequency), the duration of a single pulse is 1 second (shorter duration), and the total backwashing time is 30 seconds. High-frequency, short-duration pulses exert a stronger impact on the membrane fibers, making them suitable for situations where contaminants have strong adhesion and require strong peeling.

[0128] Example 6

[0129] The difference between this embodiment and Embodiment 2 is as follows:

[0130] The rotational speed control method for the spiral guide plate 12 in step S1 is different. In this embodiment, for chemical waste with stable solid content and small fluctuations, the PLC control system does not use a piecewise linear control model to automatically calculate the rotational speed. Instead, the operator manually sets a fixed rotational speed value (e.g., 800 r / min) based on experience through the human-machine interface, and the device runs continuously at this fixed speed. This control method is suitable for treating chemical waste with fixed sources and stable water quality, and the control system is simpler.

[0131] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A solid-liquid purification device for chemical waste, characterized in that, It includes a primary separation chamber (1), a secondary filtration chamber (2), and a precision purification chamber (3) connected sequentially along the waste liquid flow direction. The primary separation chamber (1) is equipped with a cyclone separation mechanism, which includes a cyclone cylinder (11) and a spiral guide plate (12) disposed inside the cyclone cylinder (11). The pitch of the spiral guide plate (12) gradually decreases along the downward flow direction of the waste liquid. A waste inlet (13) is opened on the side wall of the cyclone cylinder (11), a heavy phase outlet (14) is provided at the bottom, and a light phase outlet (15) is provided at the top. The secondary filtration chamber (2) is equipped with a multi-stage gradient filtration mechanism and an integrated synchronous self-cleaning component. The multi-stage gradient filtration mechanism includes multi-stage filter screens with progressively smaller apertures along the waste liquid flow direction. The integrated synchronous self-cleaning component includes multiple cleaning scrapers (24), a single cleaning drive mechanism (25), and a solid collection tank (27). The multiple cleaning scrapers (24) are attached to each filter screen and fixed to the same mounting frame (26). The cleaning drive mechanism (25) drives the mounting frame (26) to drive all the cleaning scrapers (24) to move synchronously back and forth. The direction of movement of the cleaning scrapers (24) is perpendicular to the waste liquid flow direction. An independent solid collection tank (27) is matched below each filter screen. A slag discharge port (28) is opened at the bottom of the solid collection tank (27). The precision purification chamber (3) is equipped with a membrane separation component and a pulse backwashing component; the membrane separation component includes hollow fiber membrane filaments (31); the pulse backwashing component includes a backwashing pipeline (32), a backwashing pump (33), and a pulse generator (34), the pulse generator (34) is located on the backwashing pipeline (32) and is used to output pulse cleaning water flow; The light phase outlet (15) of the primary separation chamber (1) is connected to the inlet of the secondary filtration chamber (2) through the first connecting pipe (4), and the outlet of the secondary filtration chamber (2) is connected to the inlet of the precision purification chamber (3) through the second connecting pipe (5); the first connecting pipe (4) is equipped with a first control valve (41), and the second connecting pipe (5) is equipped with a second control valve (51); The primary separation chamber (1), secondary filtration chamber (2), and precision purification chamber (3) are three-stage chambers that work together to purify the waste liquid: the primary separation chamber (1) uses a gradually pitched spiral guide plate (12) to enhance centrifugal separation and remove large solid particles from the waste liquid; the secondary filtration chamber (2) uses a synchronous transverse scraper to remove the flocs trapped by each level of filter screen and trap intermediate particle suspended matter step by step; the precision purification chamber (3) uses pulsed water flow to backwash the hollow fiber membrane filaments (31) and remove colloidal pollutants inside the membrane. The three stages work together to achieve long-cycle continuous purification.

2. The chemical waste solid-liquid purification device according to claim 1, characterized in that, The primary separation chamber (1) is also equipped with a flocculant addition mechanism; the flocculant addition mechanism includes a flocculant storage tank (16), a metering pump (17), and a dosing ring pipe (18) arranged around the inner wall of the swirl cylinder (11), with dosing holes evenly opened in the dosing ring pipe (18).

3. The chemical waste solid-liquid purification device according to claim 1, characterized in that, The multi-stage filter screen includes a first filter screen (21), a second filter screen (22), and a third filter screen (23) arranged sequentially along the flow direction of the waste liquid; the first filter screen (21) has a pore size of 0.5-2mm, the second filter screen (22) has a pore size of 0.1-0.5mm, and the third filter screen (23) has a pore size of 0.01-0.1mm.

4. The chemical waste solid-liquid purification device according to claim 1, characterized in that, The cleaning drive mechanism (25) is an electric push rod or a hydraulic cylinder, and the gap between the cleaning scraper (24) and the corresponding filter screen surface is controlled to be 0.5-2mm.

5. The chemical waste solid-liquid purification device according to claim 1, characterized in that, An aeration mechanism is set inside the precision purification chamber (3) below the membrane separation component. The aeration mechanism includes an aeration pipe (35) and a microporous aeration disc (36).

6. The chemical waste solid-liquid purification device according to claim 1, characterized in that, It is also equipped with a PLC control system; the PLC control system is electrically connected to the first control valve (41), the second control valve (51), the cleaning drive mechanism (25), the backwash pump (33), the pulse generator (34), the metering pump (17), and the aeration mechanism respectively, so as to realize the linkage control of the actions of each unit.

7. The chemical waste solid-liquid purification device according to claim 1, characterized in that, The cyclone separation mechanism also includes a variable frequency rotary drive assembly; the variable frequency rotary drive assembly includes a drive shaft, a variable frequency motor and a frequency converter; the spiral guide plate (12) is fixedly installed on the drive shaft, the drive shaft extends upward to the top of the cyclone cylinder (11) and is connected to the output shaft of the variable frequency motor; the frequency converter is electrically connected to the PLC control system, and the PLC controls the speed of the variable frequency motor through the frequency converter to realize stepless adjustment of the rotation speed of the spiral guide plate (12) from 0-1500r / min.

8. The chemical waste solid-liquid purification device according to claim 7, characterized in that, The PLC control system has a built-in piecewise linear control model for solid content and guide vane speed. Based on the solid content concentration C of the waste liquid measured by the online solid content detector, the target speed n of the spiral guide vane (12) is calculated in three segments: When 0 < C ≤ 1%, n = 100 + 40000C; When 1% < C ≤ 5%, n = 500 + 75(100C − 1); When 5% < C ≤ 10%, n = 800 + 140(100C − 5); The PLC performs a limiting process on the calculated rotational speed to keep it stable within the range of 100 r / min to 1500 r / min.

9. A method of using the chemical waste solid-liquid purification device according to any one of claims 1-8, characterized in that, Includes the following steps: S1. Coarse particle cyclone classification and separation: Chemical waste liquid is sent into the cyclone cylinder (11) from the waste inlet (13). The waste liquid spirals down along the gradually changing pitch spiral guide plate (12). Under the action of centrifugal force, the high specific gravity solid particles adhere to the cylinder wall and settle to the bottom and are discharged from the heavy phase outlet (14); the low specific gravity liquid phase and fine suspended matter flow out from the top light phase outlet (15); S2, Multi-stage synchronous self-cleaning gradient filtration: The waste liquid after primary separation enters the secondary filtration chamber (2) and passes through the multi-stage filter screen with decreasing pore size in sequence to intercept the intermediate particle size flocs; the cleaning drive mechanism (25) drives the overall mounting frame (26) to move laterally back and forth at regular intervals, and the cleaning scraper (24) simultaneously scrapes off the solid phase intercepted on the surface of each stage of the filter screen, and the solid phase falls into the solid collection tank (27) below and is discharged through the slag discharge port (28); S3, Hollow Fiber Membrane Precision Purification: After secondary filtration and buffering, the waste liquid enters the precision purification chamber (3), passes through the hollow fiber membrane fiber (31) to complete the deep interception of colloids and trace suspended solids, and the purified liquid is discharged from the outlet (37) of the precision purification chamber (3). S4. Pressure difference triggers pulse backwashing: Real-time monitoring of the filtration pressure difference on both sides of the membrane module. When the pressure difference reaches the preset threshold, the backwashing pump (33) and pulse generator (34) are started. The pulse water flow flows from the inside of the hollow fiber membrane filament (31) to the outside in reverse, stripping away the colloidal pollutants trapped in the membrane filament pores and completing membrane regeneration.

10. The method of using the chemical waste solid-liquid purification device according to claim 9, characterized in that, In step S1, flocculant is added simultaneously at a rate of 0.01%-0.1% of the waste liquid volume. In step S2, the cleaning scraper (24) performs a complete scraping cycle every 5-30 minutes; The preset threshold for differential pressure in step S4 is 1.5-2.0 times the initial operating differential pressure; the pulse backwashing frequency is 1-10Hz, and the duration of a single pulse is 1-5s.

Images