Production process and production equipment for solvent recovery

Abstract

The invention discloses a production process and production equipment for solvent recovery, the production equipment comprises a treatment case, the treatment case is a cavity shell with a rectangular structure, one side of the treatment case is provided with a waste liquid storage tank, and the waste liquid storage tank is connected with the treatment case through a feeding control pump; a multi-stage filter membrane treatment structure and a pretreatment structure are arranged in the treatment box body in a linear array; the invention relates to the technical field of chemical production, through integrated module design and intelligent process control, a'buffering-filtering-complex breaking-adsorption-membrane separation 'short-flow process is constructed, efficient recovery of a PVC waste liquid solvent is realized, the deployment cost is reduced due to overall skid-mounting of equipment, and the service life of a membrane is greatly prolonged due to dynamic pressure difference control; the preposed chlorination-resin unit reduces the membrane pollution load by more than 90%, the flow linkage dosing system improves the medicament utilization rate by 30%, and the problems of high energy consumption of a rectification method and low efficiency-cost ratio of membrane separation are comprehensively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical production, in particular to a production process and production equipment for solvent recovery. Background Art

[0002] In modern chemical production, solvent recovery is a core technical link for achieving resource recycling and reducing environmental pollution. Taking the PVC processing industry as an example, its mainstream production process is accompanied by the generation of a large amount of by-product waste liquid containing ethylene dichloride. During the distillation of vinyl chloride monomer, the residual liquid discharged from the bottom of the high-boiling tower can reach more than 800 tons per year, of which the ethylene dichloride content exceeds 65%, but it is also mixed with more than 20 impurities such as vinyl chloride monomer, trichloroethylene, and tetrachloroethane. If it is sold directly as a mixed solvent, the added value of the product is low, and the vinyl chloride in the residual liquid has the risk of volatilization and explosion during storage and transportation, as well as hidden environmental pollution hazards. What is more serious is that my country's calcium carbide method PVC production capacity accounts for as much as 60%. Processing 1 ton of PVC will produce 1.59 tons of calcium carbide mud waste residue, with an annual emission of more than 10 million tons. Traditional landfill treatment requires a large amount of land and increases environmental protection costs. Therefore, by efficiently recovering ethylene dichloride from waste solvents, it can not only reduce raw material consumption and hazardous waste treatment costs, but also promote the transformation of the industrial chain to a green circular economy.

[0003] For waste solvents containing ethylene dichloride, the mainstream industrial recovery processes include physical separation, chemical conversion and combined processes. The more common ones are: adsorption, condensation, membrane filtration and distillation. Among them, distillation has become the mainstream choice for regeneration treatment due to its mature engineering scalability and efficient product purity control. The distillation method mainly adopts the leading process of high-boiling point waste solvent purification and achieves separation through the difference in component volatility. However, the current distillation process has interference from near-boiling point impurities that need to be converted into high-boiling point alkanes through chlorination addition, and high-temperature coking problems that require the introduction of negative pressure operation to lower the boiling point and reduce polymer formation. Therefore, there are problems of safety and high energy consumption during distillation. For example, distillation requires heating the waste liquid to achieve phase change and separation of the components, which requires strict temperature control and high energy demand. In addition, the high-temperature polymerization side reaction of the distillation reboiler will produce secondary pollution such as activated carbon.

[0004] In view of the problems existing in the distillation method, the use of membrane treatment method can effectively circumvent the problems, and the membrane treatment method has demonstrated significant market value in the field of solvent recovery: the demand in the high-end field is clear, but in the mid- and low-end fields, process optimization is needed to reduce costs and increase efficiency. The problem that limits the further development of membrane treatment method is that the load of membrane separation in the mid- and low-end fields is too large, the membrane consumption is high, and there is a lack of pre-treatment means, which makes it difficult to achieve dynamic control of membrane flux during the membrane separation process. If the membrane reactor can be fully utilized and multi-stage separation treatment can be carried out in the mid- and low-end fields, its cost-effectiveness can be improved, and the solvent recovery work can be handled in a more environmentally friendly and healthy way.

[0005] In summary, solvent recovery is not only a separation engineering technology, but also a key link for chemical companies to achieve a circular economy. Given the characteristics of waste dichloroethane, a by-product of the chemical industry, how to solve the pain points in the current solvent recovery process and solvent recovery equipment production is an urgent problem to be solved. In view of this, in-depth research on the above issues led to the emergence of this case. Summary of the Invention

[0006] In view of the deficiencies of the prior art, the present invention provides a production process and production equipment for solvent recovery, which solves the problems of the prior art.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions: a production equipment for solvent recovery, comprising a processing chassis, the processing chassis being a rectangular hollow shell, a waste liquid storage tank being provided on one side of the processing chassis, the waste liquid storage tank being connected to the processing chassis via a feed control pump, and a multi-stage filter membrane processing structure and a pretreatment structure being provided in a linear array within the processing chassis;

[0008] The multi-stage membrane treatment structure includes a support frame as the main structure, a plurality of membrane treatment components arranged in a matrix and mounted on the support frame, a diversion water supply component mounted on the support frame, and a discharge pipeline connecting the plurality of membrane treatment components;

[0009] The split water supply component passes the water treated by the pretreatment structure into a plurality of membrane treatment components, which separate isomers and macromolecular materials. The membrane treatment components are equipped with a built-in dynamic pressure difference controller to control the internal and external pressure difference. The various components separated by the membrane treatment components are discharged through the discharge pipeline.

[0010] The pretreatment structure includes a dosing filter processor, the dosing filter processor is connected to a feed control pump, the dosing filter processor and the feed control pump are connected via a buffer tank, the dosing filter processor is connected to a resin adsorption tank, and the resin adsorption tank is connected to a diversion water supply component;

[0011] The wastewater entering from the feed control pump is buffered and precipitated through a buffer tank to precipitate some of the solid impurities, and then enters the dosing filter processor. The dosing filter processor is equipped with an adaptive adjustment component to adjust the dosage. The waste liquid is flocculated and chlorinated through the dosing treatment. The filtered waste liquid enters the resin adsorption tank, which adsorbs heavy metal ions and isomers respectively. The pretreated waste liquid is then subjected to solvent separation to effectively reduce the working pressure of the membrane component.

[0012] A negative pressure collection tank is provided on the outside of the processing chassis, the negative pressure collection tank is connected to the discharge pipeline, and the negative pressure collection tank is used to collect the separated solvent.

[0013] The processing chassis is a container-type structure and a reinforcement frame welded with channel steel is provided on the bottom surface. The bottom surface of the processing chassis is provided with at least two pairs of height-adjustable legs, and a hook is provided on the processing chassis.

[0014] The feed control pump is installed on the processing machine box. The feed control pump is connected with a feed pipe, and the feed pipe is connected to the waste liquid storage tank through a quick connector.

[0015] The membrane treatment assembly includes a fixed cylinder connected to a support frame, an ultrafiltration tube is installed in the fixed cylinder, a plurality of through holes are distributed around the ultrafiltration tube, a treatment membrane cylinder is sleeved on the outside of the ultrafiltration tube, and the treatment membrane cylinder is wrapped around the ultrafiltration tube. The treatment membrane cylinder is a double-layer structure, and the double-layer membranes are an ultrafiltration membrane and a reverse osmosis membrane;

[0016] The dynamic differential pressure controller includes a dynamic water inlet, a dynamic water inlet is provided on the top of the ultrafiltration tube, a water inlet controller is provided on the dynamic water inlet, the water inlet controller controls the flux through an electromagnet, and a pair of pressure sensors are provided on the inner and outer sides of the ultrafiltration tube respectively, and the electromagnet is controlled to work according to the pressure difference between the pair of pressure sensors;

[0017] The water inlet controller specifically includes a radially sealed gate, a piston that controls the telescopic movement of the gate, a sleeve connected to the outside of the dynamic water inlet, the piston can move axially in the sleeve, the electromagnet is arranged at the end of the sleeve, and a return spring and a control magnet are respectively provided on the piston. The electromagnet controller controls the magnetic force according to the pressure difference of a pair of pressure sensors, so that the piston pushes the gate to intermittently or partially close the dynamic water inlet, thereby controlling the water inlet amount and rate.

[0018] The diversion water supply assembly includes a main control pipe, which is connected to several diversion pipes. Several of the diversion pipes are connected to the end covers of several fixed cylinders and then connected to the ultrafiltration tube. The main control pipe is connected to the resin adsorption tank. A three-way valve is provided on the main control pipe, and the three-way valve is respectively connected to the main control pipe, the resin adsorption tank and the cleaning pipeline.

[0019] The negative pressure collection tank includes a storage tank body, which is arranged on the side of the processing box through a fixing frame. A negative pressure pipe is provided on the storage tank body, and a vacuum pump is connected to the negative pressure pipe. A discharge pipe extends from one side of the storage tank body, and the discharge pipe is connected to the discharge pipeline.

[0020] The dosing filter processor includes a filter housing, which is arranged in a processing box. A filter inlet pipe is provided on one side of the filter housing and is connected to the upper part of the buffer tank. A doser is also provided on the filter inlet pipe. A flow rate controller is provided on the filter inlet pipe and is linked to the doser. The flow rate controller controls the dosing rate of the doser. A separation screen is provided in the filter housing.

[0021] The flow rate controller comprises a sliding groove movably mounted on the filter inlet pipe, a circular sliding ring movably mounted in the sliding groove, a driving blade mounted in the circular sliding ring, a driving gear sleeved outside the circular sliding ring, an output gear coupled to the driving gear, and an encoder linked to the output gear;

[0022] The dosing device adopts a pusher drug delivery method, and the speed of the drug delivery is controlled by the signal output by the encoder after being processed by the controller.

[0023] A chlorination processor is provided on one side of the doser, and the chlorination processor injects chlorine into the waste liquid by aeration, breaks the chlorination by chlorination, and the aeration rate is controlled integrally by a flow rate controller.

[0024] The resin adsorption tank is integrated with the water molecular sieve. The resin adsorption tank contains a macroporous adsorption resin with a cross-linked polystyrene matrix and modified with sulfur / nitrogen functional groups, and a zeolite adsorption material composed of SiO4 and AlO4 tetrahedrons and connected by oxygen bridges to form three-dimensional channels.

[0025] A production process for solvent recovery comprises the following steps:

[0026] Step 1: Dynamic filtration and oil phase enrichment: The PVC waste liquid in the waste liquid storage tank is continuously transported to the buffer tank via a feed control pump. The buffer tank has a built-in inclined stainless steel filter. When the waste liquid flows through the filter, particles and solid impurities larger than 100 microns are intercepted. The light phase oil rich in dichloroethane on the upper layer overflows to the dosing filter processor, and the heavy phase impurities at the bottom are discharged regularly.

[0027] Step 2: Dosing, complex breaking, and solid-liquid separation: The dosing filter receives the oily waste liquid, and the flow rate controller and the doser are linked to add PAC flocculant and PAM coagulant in proportion. The chlorination processor injects chlorine by aeration to decompose the complex, converting isomers with similar polarity into tetrachloroethane. After the reaction, the waste liquid flows through the separation screen, and the flocculants and complex breaking residues are intercepted and discharged.

[0028] Step 3: Deep removal of impurities from the resin: The filtrate enters the resin adsorption tank, and the tank is designed in layers:

[0029] Upper macroporous resin: Based on cross-linked polystyrene, the sulfur-containing functional groups specifically adsorb heavy metals such as mercury and tin, while the nitrogen-containing functional groups capture isomers such as vinyl chloride monomer;

[0030] Lower layer zeolite molecular sieve: The three-dimensional pore structure selectively adsorbs water and small molecular polar impurities, with an isomer removal rate of ≥90%, reducing the subsequent membrane separation load;

[0031] Step 4: Ultrafiltration dynamic anti-fouling separation: The effluent from the resin tank is evenly distributed to each membrane treatment component through the diversion water supply component; the ultrafiltration membrane cartridge serves as the first-level separation, and the PVDF ultrafiltration membrane operates under the control of the dynamic pressure differential balance system. The pressure sensor on the inner / outer wall of the ultrafiltration tube monitors the pressure differential in real time. When the pressure differential approaches 0.3 MPa, the electromagnet drives the water inlet controller to reduce the flow rate. After the pressure differential drops to a safe value, the flux is restored to intercept colloids and macromolecular organic matter to prevent fouling and clogging of the reverse osmosis membrane;

[0032] Step 5: Reverse osmosis solvent refining: The ultrafiltration permeate enters the reverse osmosis membrane cartridge, and the polyamide composite membrane operates at a pressure of 1.8-2.2 MPa. The ethylene dichloride molecules are efficiently retained, and the inorganic salts and residual isomers are discharged with the concentrate. The permeate side produces an enriched solution with an EDC concentration of ≥15%.

[0033] Step 6: Negative pressure, low temperature, stable quality collection: The enriched liquid enters the negative pressure collection tank through the discharge pipeline, and the vacuum pump maintains a vacuum degree of 0.09 MPa in the tank; the crude EDC is collected at a low temperature of 30-35°C, with a purity of ≥95%, and discharged through the discharge pipe;

[0034] Step 7: Intelligent membrane protection cleaning: When the membrane fouling index exceeds the standard or the pressure difference persists abnormally for 10 minutes, the three-way valve automatically switches to the cleaning circuit; the circulation pump injects citric acid and sodium hydroxide cleaning solution to reversely flush the ultrafiltration and reverse osmosis membrane cartridges; after completion, the membrane flux recovery rate is self-checked, and if it meets the standard, it will switch back to the production process.

[0035] Beneficial effects

[0036] The present invention provides a production process and equipment for solvent recovery. These processes have the following beneficial effects: through integrated modular design and intelligent process control, a short process flow of "buffering-filtration-decomposition-adsorption-membrane separation" is constructed to achieve efficient solvent recovery from PVC waste liquid. The skid-mounted design reduces deployment costs, dynamic differential pressure control significantly extends membrane life, a pre-chlorination-resin unit reduces membrane contamination by >90%, and a flow-linked dosing system increases reagent utilization by 30%. This comprehensively addresses the challenges of high energy consumption in distillation and low efficiency and cost-effectiveness in membrane separation. The process also offers the following advantages:

[0037] 1: Overall modular design, intensive and efficient, container-type chassis integrates pretreatment, membrane separation, and collection units, channel steel reinforcement frame ensures transportation stability, adjustable legs adapt to complex foundations, module matrix arrangement supports flexible expansion of production capacity, and lifting interface enables rapid deployment within 48 hours, saving space compared to traditional processes and significantly shortening the installation cycle.

[0038] 2: Dynamic pressure difference balance, membrane life doubled, dual pressure sensors inside and outside the ultrafiltration membrane monitor the pressure difference in real time, when it approaches 0.3MPa, the electromagnet links the water inlet controller to reduce the flow rate, removes pollutants through shear force changes, and automatically restores the flux when the pressure difference drops, reducing the frequency of chemical cleaning and effectively extending the membrane life.

[0039] 3: Pre-deep impurity removal, sharp reduction of membrane load, chlorination and decomposition of isomers into tetrachloroethane, removal rate of 96%, simultaneous adsorption of heavy metal Hg by layered resin tank 2+ >99.9% and tetrachloroethane, the capture rate of zeolite molecular sieve is 90%, the viscosity of the waste liquid after pretreatment decreases by 70%, the membrane flux maintains 40LMH / bar, and the pollution index decreases by 85%.

[0040] 4. Intelligent dosing linkage, optimized operating costs, the flow rate controller encoder monitors the flow in real time, and the PAC / PAM doser and chlorine aeration valve are linked to reduce the deviation between the dosage of the agent and the flow rate, improve the utilization rate of chlorine, and reduce the overall cost of treating a ton of waste liquid by 18% compared with manual control. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The present invention provides a process flow chart of a solvent recovery production process.

[0042] Figure 2 This is a first stereoscopic structural schematic diagram of a solvent recovery production equipment according to the present invention.

[0043] Figure 3 This is a second three-dimensional structural schematic diagram of a solvent recovery production equipment according to the present invention.

[0044] Figure 4 This is a third stereoscopic structural schematic diagram of a solvent recovery production equipment according to the present invention.

[0045] Figure 5 This is a schematic diagram of the main structure of a solvent recovery production equipment according to the present invention.

[0046] Figure 6 This is a schematic diagram of the pretreatment structure of a solvent recovery production equipment described in the present invention.

[0047] Figure 7 This is a schematic structural diagram of a dosing filter processor of a solvent recovery production equipment described in the present invention.

[0048] Figure 8 A production equipment for solvent recovery according to the present invention Figure 7 Schematic diagram of the local enlarged structure.

[0049] Figure 9 This is a schematic diagram of the multi-stage membrane processing structure of a solvent recovery production equipment described in the present invention.

[0050] Figure 10 This is a schematic cross-sectional structural diagram of a membrane treatment component of a solvent recovery production equipment according to the present invention.

[0051] Figure 11 A production equipment for solvent recovery according to the present invention Figure 10 Schematic diagram of the local enlarged structure.

[0052] In the figure: 1. Processing chassis; 2. Waste liquid storage tank; 3. Feed control pump; 4. Multi-stage membrane treatment structure; 5. Pretreatment structure; 6. Negative pressure collection tank; 11. Reinforcement frame; 12. Support legs; 13. Hook; 31. Feed pipe; 32. Quick connector; 41. Support frame; 42. Membrane treatment component; 43. Diverter water supply component; 44. Discharge pipeline; 51. Buffer tank; 52. Dosing filter processor; 53. Resin adsorption tank; 54. Chlorination processor; 61. Storage tank; 62. Fixed frame; 63. Negative pressure pipe; 64. Vacuum pump; 65. Feed pipe; 421. Fixed cylinder; 422. Ultrafiltration tube; 423. Processing membrane cylinder; 424, dynamic water inlet; 425, water inlet controller; 426, pressure sensor; 431, main control tube; 432, diverter tube; 433, three-way valve; 521, filter housing; 522, filter inlet pipe; 523, doser; 524, flow rate controller; 525, separation screen; 4251, gate; 4252, piston; 4253, sleeve; 4254, return spring; 4255, control magnet; 4256, electromagnet; 5241, sliding groove; 5242, annular slip ring; 5243, drive blade; 5244, drive gear; 5245, output gear; 5246, encoder. DETAILED DESCRIPTION

[0053] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0054] See also Figure 1-11The present invention provides an implementation scheme: in modern chemical production, especially in the PVC production process, the solvent in the wastewater can be recycled and reused. Conventional solvent recovery process equipment mainly uses distillation. The current distillation means have problems with safety and high energy consumption. For example, distillation requires heating the waste liquid to make the components undergo phase change and complete separation, which requires strict temperature control and high energy demand. In addition, the high-temperature polymerization side reaction of the distillation reboiler will produce secondary pollution such as activated carbon. In view of the problems existing in the distillation method, the use of membrane treatment can effectively circumvent the problems, but the cost-effectiveness advantage of membrane treatment in the mid- and low-end fields is not obvious. For example, in the PVC recovery process, a further problem of limiting the membrane treatment method is that the isomers contained in the PVC waste liquid cannot be separated by conventional membranes, and these waste liquids are usually highly viscous, and the service life of the membrane reactor is short. Therefore, process optimization is needed to reduce costs and increase efficiency.

[0055] Example 1: In order to solve the above problems, the present application discloses a production process for solvent recovery, comprising the following steps:

[0056] Step 1: Dynamic filtration and oil phase enrichment: The PVC waste liquid in the waste liquid storage tank is continuously transported to the buffer tank via a feed control pump. The buffer tank has a built-in inclined stainless steel filter. When the waste liquid flows through the filter, particles and solid impurities larger than 100 microns are intercepted. The light phase oil rich in dichloroethane on the upper layer overflows to the dosing filter processor, and the heavy phase impurities at the bottom are discharged regularly.

[0057] Step 2: Dosing, complex breaking, and solid-liquid separation: The dosing filter receives the oily waste liquid, and the flow rate controller and the doser are linked to add PAC flocculant and PAM coagulant in proportion. The chlorination processor injects chlorine by aeration to decompose the complex, converting isomers with similar polarity into tetrachloroethane. After the reaction, the waste liquid flows through the separation screen, and the flocculants and complex breaking residues are intercepted and discharged.

[0058] Step 3: Deep removal of impurities from the resin: The filtrate enters the resin adsorption tank, and the tank is designed in layers:

[0059] Upper macroporous resin: Based on cross-linked polystyrene, the sulfur-containing functional groups specifically adsorb heavy metals such as mercury and tin, while the nitrogen-containing functional groups capture isomers such as vinyl chloride monomer;

[0060] Lower layer zeolite molecular sieve: The three-dimensional pore structure selectively adsorbs water and small molecular polar impurities, with an isomer removal rate of ≥90%, reducing the subsequent membrane separation load;

[0061] Step 4: Ultrafiltration dynamic anti-fouling separation: The effluent from the resin tank is evenly distributed to each membrane treatment component through the diversion water supply component; the ultrafiltration membrane cartridge serves as the first-level separation, and the PVDF ultrafiltration membrane operates under the control of the dynamic pressure differential balance system. The pressure sensor on the inner / outer wall of the ultrafiltration tube monitors the pressure differential in real time. When the pressure differential approaches 0.3 MPa, the electromagnet drives the water inlet controller to reduce the flow rate. After the pressure differential drops to a safe value, the flux is restored to intercept colloids and macromolecular organic matter to prevent fouling and clogging of the reverse osmosis membrane;

[0062] Step 5: Reverse osmosis solvent refining: The ultrafiltration permeate enters the reverse osmosis membrane cartridge, and the polyamide composite membrane operates at a pressure of 1.8-2.2 MPa. The ethylene dichloride molecules are efficiently retained, and the inorganic salts and residual isomers are discharged with the concentrate. The permeate side produces an enriched solution with an EDC concentration of ≥15%.

[0063] Step 6: Negative pressure, low temperature, stable quality collection: The enriched liquid enters the negative pressure collection tank through the discharge pipeline, and the vacuum pump maintains a vacuum degree of 0.09 MPa in the tank; the crude EDC is collected at a low temperature of 30-35°C, with a purity of ≥95%, and discharged through the discharge pipe;

[0064] Step 7: Intelligent membrane protection cleaning: When the membrane fouling index exceeds the standard or the pressure difference persists abnormally for 10 minutes, the three-way valve automatically switches to the cleaning circuit; the circulation pump injects citric acid and sodium hydroxide cleaning solution to reversely flush the ultrafiltration and reverse osmosis membrane cartridges; after completion, the membrane flux recovery rate is self-checked, and if it meets the standard, it will switch back to the production process.

[0065] Example 2: According to the instructions attached Figure 2 -Attached Figure 11 It can be seen that in order to cooperate with the application of the above-mentioned process, the present application also discloses a solvent recovery production equipment, including a processing chassis 1, the processing chassis 1 is a hollow shell with a rectangular structure, a waste liquid storage tank 2 is provided on one side of the processing chassis 1, the waste liquid storage tank 2 and the processing chassis are connected by a feed control pump 3, the feed control pump 3 provides initial power to stably and continuously pump the waste liquid from the waste liquid storage tank 2 into the subsequent processing unit, and a multi-stage filter membrane processing structure 4 and a pretreatment structure 5 are arranged in a linear array in the processing chassis;

[0066] The processing chassis 1 is a container-type structure and a reinforcement frame 11 welded with channel steel is provided on the bottom. The reinforcement frame 11 greatly enhances the overall structural strength and rigidity of the equipment, ensuring the stability of the internal precision components during transportation and operation. The bottom of the processing chassis 1 is provided with at least two pairs of height-adjustable legs 12. The adjustable legs 12 facilitate the leveling and installation of the equipment on site and adapt to different foundation conditions. A hook 13 is provided on the processing chassis 1. The hook 13 facilitates the overall lifting and transportation of the large container-type chassis. The feed control pump 3 is installed on the processing chassis 1. The feed control pump 3 is connected to a feed pipe 31, and the feed pipe 31 is connected to the waste liquid storage tank 2 through a quick connector 32.

[0067] According to the instruction manual Figure 2 -Attached Figure 11 It can be seen that the multi-stage membrane treatment structure 4 includes a support frame 41 as the main structure, a plurality of membrane treatment components 42 arranged in a matrix on the support frame 41, a diversion water supply component 43 installed on the support frame, and a discharge pipe 44 connecting the plurality of membrane treatment components 42; the support frame 41 provides rigid support and positioning reference for the entire membrane treatment area, ensuring stable installation and precise alignment of the array of membrane treatment components 42; the plurality of membrane treatment components 42 arranged in a matrix realizes modularization and scalability of treatment capacity, facilitating maintenance and expansion; the diversion water supply component 43 is responsible for evenly distributing the pretreated waste liquid to the inlet of each membrane treatment unit, ensuring balanced load of each unit and avoiding local overload; the discharge pipe 44 is responsible for collecting the permeate and concentrate separated by each membrane treatment component 42, and directing them to subsequent collection or discharge points respectively;

[0068] According to the instruction manual Figure 2 -Attached Figure 11 It can be seen that the working process is that the diversion water supply component 43 passes the water treated by the pretreatment structure 5 into the several membrane treatment components 42, and the several membrane treatment components 42 separate the isomers and macromolecular materials, and the membrane treatment component 42 has a built-in dynamic pressure difference controller to control the internal and external pressure difference. The various components separated by the membrane treatment component 42 are discharged through the discharge pipeline 44. The membrane treatment component 42 uses its core ultrafiltration membrane and reverse osmosis membrane. Under the precise control of the dynamic pressure difference controller, it efficiently intercepts colloids, macromolecular organic matter, inorganic salts and isomers (such as tetrachloroethane, etc.) remaining after pre-conversion / adsorption, while allowing the target solvent dichloroethane EDC molecules to pass through, thereby realizing the refinement and enrichment of the solvent.

[0069] According to the instruction manual Figure 2 -Attached Figure 8 As can be seen, the pretreatment structure 5 includes a dosing filter processor 52, which is connected to the feed control pump 3. The dosing filter processor 52 and the feed control pump 3 are connected through a buffer tank 51. The buffer tank 51 has a built-in inclined stainless steel filter. After the waste liquid enters the buffer tank 51, the flow rate is reduced, and particles larger than 100 microns and solid impurities are intercepted by the filter and slide to the bottom of the tank, achieving preliminary solid-liquid separation; the upper EDC-rich light phase oil overflows, and the heavy phase impurities at the bottom can be discharged regularly, reducing the load for subsequent processing and providing relatively clean oil phase raw materials. The dosing filter processor 52 is connected to a resin adsorption tank 53, which is connected to the diversion water supply component 43;

[0070] According to the instruction manual Figure 2 -Attached Figure 8It can be seen that the dosing filter processor 52 is the core unit of network breaking and flocculation. The adaptation and adjustment component arranged on it includes a flow rate controller 524 and a dosing device 523 linkage mechanism, which accurately adjusts the addition ratio of PAC flocculant and PAM coagulant aid according to the real-time flow rate to ensure the best flocculation effect; its built-in separation screen 525 is used to intercept the alum flocs and network breaking residues produced by flocculation to complete solid-liquid separation.

[0071] According to the instruction manual Figure 2 -Attached Figure 8 It can be seen that the chlorination processor 54 efficiently disperses chlorine into the waste liquid flow through aeration, destroys the complex structure and converts some isomers with similar polarity into tetrachloroethane that is easier to subsequently process. The aeration rate is controlled by the flow rate controller 524 to ensure that the chlorine addition matches the flow rate.

[0072] According to the instruction manual Figure 2 -Attached Figure 8 It can be seen that the resin adsorption tank 53 deeply removes impurities through its layered design, with the upper layer of macroporous resin and the lower layer of zeolite molecular sieve: the upper layer of macroporous adsorption resin modified with sulfur / nitrogen functional groups specifically captures heavy metal ions such as mercury and tin, as well as isomer molecules such as vinyl chloride monomer; the lower layer of zeolite molecular sieve uses its unique three-dimensional pore structure to selectively adsorb moisture and small molecular polar impurities, with an isomer removal rate of ≥90%, significantly reducing the pollution load and treatment difficulty of subsequent membrane separation.

[0073] According to the instruction manual Figure 2 -Attached Figure 8 As can be seen, the workflow of the pretreatment structure 5 is as follows: the wastewater entering from the feed control pump 3 is buffered and precipitated in the buffer tank 51 to partially precipitate the solid impurities therein, and then enters the dosing filter processor 52. The dosing filter processor 52 is provided with an adaptive adjustment component to adjust the dosage. The wastewater is subjected to flocculation treatment and chlorination decomposition treatment through the dosing treatment. The filtered wastewater enters the resin adsorption tank 53, which adsorbs heavy metal ions and isomers respectively. The pretreated wastewater is then subjected to solvent separation, effectively reducing the working pressure of the membrane component, extending the membrane life and improving the separation efficiency. The entire pretreatment process works synergistically to convert a complex liquid with high viscosity, impurities, and isomers into a feed liquid suitable for membrane separation with a significantly reduced impurity content.

[0074] According to the instruction manual Figure 2 -Attached Figure 11It can be seen that a negative pressure collection tank 6 is provided on the outside of the above-mentioned processing chassis 1. The negative pressure collection tank 6 is connected to the discharge pipeline 44. The negative pressure collection tank 6 is used to collect the separated solvent. The negative pressure collection tank 6 maintains a vacuum degree of 0.09 MPa in the tank through the vacuum pump 64 connected to it, and works in a low temperature environment of 30-35°C. The low pressure environment significantly reduces the boiling point of EDC. Combined with low temperature control, the volatilization loss of the solvent is minimized to ensure that the collected crude EDC (concentration ≥15%) maintains high purity (≥95%) in a stable state and is safely output through the discharge pipe 65.

[0075] Then according to the instructions Figure 2-11 It can be seen that the membrane treatment assembly 42 includes a fixed cylinder 421, which is connected to the support frame 41, and an ultrafiltration tube 422 is assembled in the fixed cylinder 421. The ultrafiltration tube 422 is surrounded by a plurality of through holes. A treatment membrane cylinder 423 is provided on the outside of the ultrafiltration tube 422, and the treatment membrane cylinder 423 is wrapped around the ultrafiltration tube 422. The treatment membrane cylinder 423 is a double-layer structure, and the double-layer membranes are an ultrafiltration membrane and a reverse osmosis membrane; the fixed cylinder 421 provides protection and support for the internal membrane elements, and the ultrafiltration tube 422 and the through holes around it constitute a liquid inlet channel, so that The waste liquid can evenly contact the external treatment membrane cylinder 423. The double-layer structure of the treatment membrane cylinder 423 integrates the functions of primary ultrafiltration (PVDF ultrafiltration membrane) and secondary reverse osmosis (polyamide composite membrane) in a single compact unit: the ultrafiltration membrane first intercepts colloids and large molecular organic matter to protect the reverse osmosis membrane; the reverse osmosis membrane efficiently intercepts EDC molecules under high pressure of 1.8-2.2 MPa, so that inorganic salts and residual small molecular impurities such as residual isomers are discharged with the concentrated liquid, and high-concentration EDC enriched liquid is produced on the osmosis side. This integrated design saves space and optimizes the process.

[0076] In order to further protect the membrane layer in the membrane treatment component 42, the dynamic pressure difference controller includes a dynamic water inlet 424. The dynamic water inlet 424 is provided on the top of the ultrafiltration tube 422. A water inlet controller 425 is provided on the dynamic water inlet 424. The water inlet controller 425 controls the flux through an electromagnet 4256. A pair of pressure sensors 426 are provided on the inner and outer sides of the ultrafiltration tube 422 respectively. The water inlet controller 425 specifically includes a radially blocked gate 4251, a piston 4252 for controlling the telescopic movement of the gate 4251, a sleeve 4253 connected to the outside of the dynamic water inlet 424, the piston 4252 can move axially in the sleeve 4253, the electromagnet 4256 is provided at the end of the sleeve 4253, and a return spring 4254 and a control magnet 4255 are respectively provided on the piston 4252. The controller of the electromagnet 4256 is based on the pair of pressure sensors 4 The pressure difference of 26 controls the magnetic force, causing the piston 4252 to push the gate 4251 to intermittently or partially close the dynamic water inlet 424, thereby controlling the water inlet volume and rate. The dynamic pressure difference controller constitutes the core of the intelligent anti-fouling system: the inner / outer pressure sensor 426 monitors the pressure difference between the feed side of the inner cavity of the ultrafiltration membrane tube and the filtration side of the outer wall of the tube in real time. When the pressure difference approaches the set safety threshold due to accumulation of membrane surface pollution or unstable flow, the controller instructs the electromagnet 4256 to act and drive the water inlet controller 425 to reduce the feed flow of the membrane unit. The reduced flow causes the shear force on the membrane surface to change, which helps to peel off or slow down the deposition of pollutants, thereby causing the pressure difference to fall below the safe value. The water inlet controller 425 then restores the flux. This dynamic regulation process effectively prevents serious clogging of the membrane pores, significantly extends the service life of the ultrafiltration membrane and the downstream reverse osmosis membrane, and ensures continuous and stable operation of the system.

[0077] Furthermore, the above-mentioned diversion water supply component 43 includes a main control pipe 431, and the main control pipe 431 is connected to a plurality of diversion pipes 432. The plurality of diversion pipes 432 are connected to the end covers of the plurality of fixed cylinders 421 and then communicated with the ultrafiltration tube 422. The main control pipe 431 is connected to the resin adsorption tank 53. The main control pipe 431 is provided with a three-way valve 433. The three-way valve 433 is respectively connected to the main control pipe 431, the resin adsorption tank 53 and the cleaning pipeline. The main pipe 431 receives the water from the resin adsorption tank 53. The qualified pre-treated liquid in tank 53 is evenly distributed by several shunt pipes 432 to the inlet of the ultrafiltration tube 422 of each membrane treatment component 42 through the main control pipe 431. The shunt pipes 432 are connected through the end cover of the fixed cylinder 421. The three-way valve 433 is the key switching point: during normal production, the valve connects the main control pipe 431 and the membrane component; when cleaning is required, the valve automatically switches, disconnects the production liquid, and connects the cleaning circuit, so that the cleaning liquid can be injected into the membrane system through the circulation pump for back flushing.

[0078] According to the instruction manual Figure 2 -Attached Figure 8It can be seen that the above-mentioned dosing filter processor 52 includes a filter housing 521, which is arranged in the processing box 1, and a filter inlet pipe 522 is provided on one side of the filter housing 521 and is connected to the upper part of the buffer tank 51. A doser 523 is also provided on the filter inlet pipe 522, and a flow rate controller 524 is provided on the filter inlet pipe 522 to be linked to the doser 523. The flow rate controller 524 controls the dosing rate of the doser 523, and a separation screen 525 is provided in the filter housing 521; the filter housing 521 accommodates the flocculation, chlorination reaction and solid-liquid separation processes; the filter inlet pipe 522 introduces the light phase oil overflowing from the buffer tank 51 into the processor. The flow rate controller 524 is the core sensing and driving component of the adaptive adjustment component. It monitors the liquid inlet flow in real time. The dosing device 523 accurately measures and adds PAC and PAM agents through its propulsion mechanism according to the flow signal provided by the flow rate controller 524, ensuring that the dosage and flow rate are in a set ratio to achieve the best flocculation effect. The separation screen 525 physically intercepts the floccules generated by the reaction and the residues produced by the broken network, thereby purifying the liquid after the reaction.

[0079] According to the instruction manual Figure 2 -Attached Figure 8 As can be seen, the flow rate controller 524 comprises a sliding groove 5241 movably mounted on the filter inlet pipe 522, a rotating slip ring 5242 movably mounted in the sliding groove 5241, a driving blade 5243 mounted in the rotating slip ring 5242, a driving gear 5244 sleeved on the outside of the rotating slip ring 5242, an output gear 5245 coupled to the driving gear 5244, and an encoder 5246 linked to the output gear 5245.

[0080] Its working process is: when the waste liquid flows through the filter inlet pipe 522, it impacts the driving blade 5243, pushing the annular slip ring 5242 to rotate in the sliding groove 5241, and the rotation of the annular slip ring 5242 is transmitted to the output gear 5245 through its external driving gear 5244. The rotation speed of the output gear 5245 is strictly positively correlated with the liquid flow rate. The encoder 5246 monitors the rotation speed or angle of the output gear 5245 and converts it into an electrical signal output representing the real-time flow rate. This signal is sent to the control system for accurately controlling the drug delivery rate of the dosing device 523, thereby achieving dynamic matching of flow rate and drug delivery.

[0081] The dosing device 523 uses a propeller to deliver the drug. The rate of delivery is controlled by the signal output by the encoder 5246 after being processed by the controller. The propeller delivery mechanism, such as a precision metering pump or a piston 4252 driven by a stepper motor, is a common structure and is therefore not disclosed here. It receives a command signal from the controller, which is calculated based on the flow rate signal measured by the encoder 5246, and accurately adjusts the propulsion speed and stroke, thereby controlling the instantaneous dosage of PAC and PAM agents to ensure a constant concentration of the agents.

[0082] A chlorination processor 54 is provided on one side of the doser 523. The chlorination processor 54 injects chlorine into the waste liquid by aeration, and breaks the chelate by chlorination. The aeration rate is controlled by a flow rate controller 524. The chlorination processor 54 usually includes a chlorine source, a flow control valve and an aeration head. The structure here is a common structure, so it will not be further explained. The aeration rate, that is, the chlorine injection flow rate, also receives the encoder 5246 signal from the flow rate controller 524. The controller adjusts the opening of the chlorine flow control valve according to a preset ratio to ensure that the chlorine dosage always matches the waste liquid treatment volume, thereby achieving an efficient and stable chelate breaking reaction and converting the target isomer into tetrachloroethane.

[0083] The resin adsorption tank 53 is integrated with the water molecular sieve. The resin adsorption tank 53 contains a macroporous adsorption resin based on cross-linked polystyrene and modified with sulfur / nitrogen functional groups, and a zeolite adsorption material composed of SiO4 and AlO4 tetrahedrons connected by oxygen bridges to form three-dimensional channels.

[0084] This integrated design combines two highly efficient adsorption materials, macroporous resin for specific chemical adsorption and zeolite molecular sieve for selective physical adsorption, into one container, making efficient use of space.

[0085] The overall working process is as follows: the pre-treated liquid enters the upper part of the tank after flocculation, chlorination and filtration, first flows through the upper macroporous resin layer, and its sulfur-containing functional groups specifically chelate Hg 2+ 、Sn 2+ The liquid then flows through the lower zeolite molecular sieve layer, whose regular micropores, typically 0.3-1 nm, preferentially adsorb water molecules and small polar impurities, such as residual small alcohols and acids, through molecular sieving and polar adsorption. It also has a good adsorption effect on the larger tetrachloroethane generated in step 2, with an isomer removal rate of ≥90%. After this deep decontamination, the liquid has significantly reduced viscosity, heavy metal, isomer, water, and small molecule impurity content, making it a high-quality feed liquid suitable for subsequent membrane separation and refining. This significantly reduces the risk of membrane fouling and processing load, extends the processing time of the membrane reactor, reduces the need for backwashing, improves efficiency, and reduces damage to the membrane reactor through dynamic pressure balance, further extending its service life.

[0086] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A production equipment for solvent recovery, comprising a processing chassis (1), wherein the processing chassis (1) is a hollow shell with a rectangular structure, a waste liquid storage tank (2) is provided on one side of the processing chassis (1), and the waste liquid storage tank (2) is connected to the processing chassis through a feed control pump (3), characterized in that: The processing box is provided with a multi-stage filter membrane processing structure (4) and a pre-processing structure (5) in a linear array; The multi-stage membrane treatment structure (4) comprises a support frame (41) as a main structure, a plurality of membrane treatment assemblies (42) arranged in a matrix and mounted on the support frame (41), a diversion water supply assembly (43) mounted on the support frame, and a discharge pipe (44) connecting the plurality of membrane treatment assemblies (42); The split water supply component (43) passes the water treated by the pretreatment structure (5) into a plurality of membrane treatment components (42), and the plurality of membrane treatment components (42) separates isomers and macromolecular materials. The membrane treatment components (42) are equipped with a built-in dynamic pressure difference controller to control the internal and external pressure difference. The various components separated by the membrane treatment components (42) are discharged through the discharge pipeline (44); The pretreatment structure (5) includes a dosing filter processor (52), the dosing filter processor (52) is connected to the feed control pump (3), the dosing filter processor (52) and the feed control pump (3) are connected via a buffer tank (51), the dosing filter processor (52) is connected to a resin adsorption tank (53), and the resin adsorption tank (53) is connected to a diversion water supply component (43); The wastewater entering from the feed control pump (3) is buffered and precipitated through a buffer tank (51) to remove some solid impurities therein, and then enters a dosing filter processor (52). An adaptor and adjustment component is provided on the dosing filter processor (52) to adjust the dosing amount. The wastewater is subjected to flocculation treatment and chlorination decomposition treatment through dosing treatment. The filtered wastewater enters a resin adsorption tank (53). The resin adsorption tank (53) adsorbs heavy metal ions and isomers respectively. The pretreated wastewater is then subjected to solvent separation to effectively reduce the working pressure of the membrane component. A negative pressure collection tank (6) is provided on the outside of the processing chassis (1), the negative pressure collection tank (6) is connected to the discharge pipeline (44), and the negative pressure collection tank (6) is used to collect the separated solvent.

2. The solvent recovery production equipment according to claim 1, characterized in that: The processing chassis (1) is a container-type structure and has a reinforcement frame (11) welded with channel steel on its bottom surface. The bottom surface of the processing chassis (1) is provided with at least two pairs of height-adjustable legs (12), and a hook (13) is provided on the processing chassis (1).

3. The production equipment for solvent recovery according to claim 2, characterized in that: The feed control pump (3) is installed on the processing machine box (1), and a feed pipe (31) is connected to the feed control pump (3), and the feed pipe (31) is connected to the waste liquid storage tank (2) through a quick connector (32).

4. The production equipment for solvent recovery according to claim 3, characterized in that: The membrane treatment assembly (42) includes a fixed cylinder (421), the fixed cylinder (421) is connected to the support frame (41), an ultrafiltration tube (422) is assembled in the fixed cylinder (421), a plurality of through holes are arranged around the ultrafiltration tube (422), a treatment membrane cylinder (423) is sleeved on the outside of the ultrafiltration tube (422), the treatment membrane cylinder (423) is wrapped around the ultrafiltration tube (422), and the treatment membrane cylinder (423) is a double-layer structure, and the double-layer membranes are respectively an ultrafiltration membrane and a reverse osmosis membrane; The dynamic differential pressure controller comprises a dynamic water inlet (424). The top of the ultrafiltration tube (422) is provided with the dynamic water inlet (424). A water inlet controller (425) is provided on the dynamic water inlet (424). The water inlet controller (425) controls the flux via an electromagnet (4256). A pair of pressure sensors (426) are respectively provided on the inner and outer sides of the ultrafiltration tube (422). The operation of the electromagnet (4256) is controlled according to the pressure difference of the pair of pressure sensors (426).

5. The production equipment for solvent recovery according to claim 4, characterized in that: The diversion water supply assembly (43) comprises a main control pipe (431), the main control pipe (431) is connected to a plurality of diversion pipes (432), the plurality of diversion pipes (432) are connected to the end covers of a plurality of fixed cylinders (421) and are further connected to the ultrafiltration tube (422), the main control pipe (431) is connected to the resin adsorption tank (53), and a three-way valve (433) is provided on the main control pipe (431), and the three-way valve (433) is respectively connected to the main control pipe (431), the resin adsorption tank (53) and the cleaning pipeline.

6. The solvent recovery production equipment according to claim 5, characterized in that: The negative pressure collection tank (6) includes a storage tank body (61), which is arranged on the side of the processing box (1) through a fixing frame (62), and a negative pressure pipe (63) is provided on the storage tank body (61), which is connected to a vacuum pump (64) through the negative pressure pipe (63). A discharge pipe (65) extends from one side of the storage tank body (61), and the discharge pipe (65) is connected to the discharge pipeline (44).

7. The solvent recovery production equipment according to claim 6, characterized in that: The dosing filter processor (52) comprises a filter housing (521), the filter housing (521) being arranged in a processing box (1), a filter inlet pipe (522) being arranged on one side of the filter housing (521) and being connected to the upper part of the buffer tank (51), a doser (523) being further arranged on the filter inlet pipe (522), a flow rate controller (524) being arranged on the filter inlet pipe (522) and being linked to the doser (523), the flow rate controller (524) controlling the dosing rate of the doser (523), and a separation screen (525) being arranged in the filter housing (521).

8. The solvent recovery production equipment according to claim 7, characterized in that: A chlorination processor (54) is provided on one side of the doser (523). The chlorination processor (54) injects chlorine into the waste liquid by aeration, and breaks the chlorination by chlorination. The aeration rate is controlled integrally by a flow rate controller (524).

9. The solvent recovery production equipment according to claim 8, characterized in that: The resin adsorption tank (53) is integrated with the water molecular sieve. The resin adsorption tank (53) is internally provided with a macroporous adsorption resin with a cross-linked polystyrene matrix and modified with sulfur / nitrogen functional groups, and a zeolite adsorption material composed of SiO4 and AlO4 tetrahedrons and connected by oxygen bridges to form three-dimensional pores.

10. A production process for solvent recovery, applied to the production equipment for solvent recovery according to any one of claims 1 to 9, characterized in that: The steps include: Step 1: Dynamic filtration and oil phase enrichment: The PVC waste liquid in the waste liquid storage tank is continuously transported to the buffer tank via a feed control pump. The buffer tank has a built-in inclined stainless steel filter. When the waste liquid flows through the filter, particles and solid impurities larger than 100 microns are intercepted. The light phase oil rich in dichloroethane on the upper layer overflows to the dosing filter processor, and the heavy phase impurities at the bottom are discharged regularly. Step 2: Dosing, complex breaking, and solid-liquid separation: The dosing filter receives the oily waste liquid, and the flow rate controller and the doser are linked to add PAC flocculant and PAM coagulant in proportion. The chlorination processor injects chlorine by aeration to decompose the complex, converting isomers with similar polarity into tetrachloroethane. After the reaction, the waste liquid flows through the separation screen, and the flocculants and complex breaking residues are intercepted and discharged. Step 3: Deep removal of impurities from the resin: The filtrate enters the resin adsorption tank, and the tank is designed in layers: Upper macroporous resin: Based on cross-linked polystyrene, the sulfur-containing functional groups specifically adsorb heavy metals such as mercury and tin, while the nitrogen-containing functional groups capture isomers such as vinyl chloride monomer; Lower layer zeolite molecular sieve: The three-dimensional pore structure selectively adsorbs water and small molecular polar impurities, with an isomer removal rate of ≥90%, reducing the subsequent membrane separation load; Step 4: Ultrafiltration dynamic anti-fouling separation: The effluent from the resin tank is evenly distributed to each membrane treatment component through the diversion water supply component; the ultrafiltration membrane cartridge serves as the first-level separation, and the PVDF ultrafiltration membrane operates under the control of the dynamic pressure differential balance system. The pressure sensor on the inner / outer wall of the ultrafiltration tube monitors the pressure differential in real time. When the pressure differential approaches 0.3 MPa, the electromagnet drives the water inlet controller to reduce the flow rate. After the pressure differential drops to a safe value, the flux is restored to intercept colloids and macromolecular organic matter to prevent fouling and clogging of the reverse osmosis membrane; Step 5: Reverse osmosis solvent refining: The ultrafiltration permeate enters the reverse osmosis membrane cartridge, and the polyamide composite membrane operates at a pressure of 1.8-2.2 MPa. The ethylene dichloride molecules are efficiently retained, and the inorganic salts and residual isomers are discharged with the concentrate. The permeate side produces an enriched solution with an EDC concentration of ≥15%. Step 6: Negative pressure, low temperature, stable quality collection: The enriched liquid enters the negative pressure collection tank through the discharge pipeline, and the vacuum machine maintains a vacuum degree of 0.09 MPa in the tank; Collect crude EDC at a low temperature of 30-35°C with a purity of ≥95% and output it through the discharge pipe; Step 7: Intelligent membrane protection cleaning: When the membrane fouling index exceeds the standard or the pressure difference persists abnormally for 10 minutes, the three-way valve automatically switches to the cleaning circuit; the circulation pump injects citric acid and sodium hydroxide cleaning solution to reversely flush the ultrafiltration and reverse osmosis membrane cartridges; after completion, the membrane flux recovery rate is self-checked, and if it meets the standard, it will switch back to the production process.

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