CN106966536A - Strong brine zero-emission film concentration technology and equipment - Google Patents

Abstract

A kind of strong brine zero-emission film concentration technology and equipment, including：Soften micro-filtration, nanofiltration membrane separation device, strong brine desalination reverse osmosis membrane apparatus, hyperconcetration device, evaporated crystallization device.The reaction thickener delivery port for softening micro-filtration is connected with softening micro-filtration water inlet, soften and pH value governor motion is provided with before the delivery port of micro-filtration, softening micro-filtration is connected in series mutually with nanofiltration membrane separation device, strong brine desalination reverse osmosis membrane apparatus, hyperconcetration device, reuse water tank, the water inlet of each equipment and delivery port, and the super brine outlet of hyperconcetration device is connected with evaporated crystallization device.Present invention process includes pre-treatment step, film concentration step.It is an advantage of the invention that by the combination of a variety of concentration technologies, effectively improving the efficiency that equipment handles strong brine, realizing the target of minimizing, the zero-emission of strong brine, reduce the operating cost of strong brine processing equipment.

Description

Concentrated brine zero discharge membrane concentration process and equipment

technical field

The invention relates to a water treatment process and equipment, in particular to a concentrated brine zero-discharge membrane concentration process and equipment.

Background technique

Zero discharge of wastewater is the goal required by the coal chemical industry and an important link to achieve sustainable and stable development. In the entire process of zero discharge of wastewater treatment, the high investment and operating costs of evaporation and crystallization devices are a major bottleneck restricting the realization of zero discharge. Therefore, the reduction and reuse of wastewater before evaporative crystallization is a key link to effectively reduce the overall treatment cost.

The concentrated brine targeted by the zero discharge device in the coal chemical industry is mainly the concentrated brine produced by the wastewater discharged from the coal chemical plant after undergoing biochemical treatment of wastewater, advanced oxidation, and double-membrane system for reclaimed water reuse, which has a high COD (chemical oxygen demand) , high salt content, high hardness, high alkalinity and other characteristics, it is impossible to directly use conventional reverse osmosis for further concentration and reuse, and because the general water volume is relatively large, it directly enters the evaporation crystallization for thermal concentration crystallization, and the investment and operation costs are high.

At present, domestic and foreign treatment methods for the reduction and reuse of such concentrated brine generally include: high-efficiency oxidation, high-efficiency reverse osmosis, forward osmosis, electrostatic desalination, membrane distillation, etc. Although there are many processing methods, they all have certain limitations in application, lack of systematic process, and cannot complete the whole process of processing, and the actual processing effect and economy are obviously lacking.

Contents of the invention

The object of the present invention is to provide a concentrated brine zero-discharge membrane concentration process and equipment for the defects in the prior art. The invention effectively increases the concentration multiple of the concentrated brine through the combination of various processes, realizes the reduction of the concentrated brine, reduces the scale of the evaporation and crystallization device, and reduces the overall operating cost. Process feature of the present invention comprises the following steps:

(1) Transport the high-concentration brine to the pretreatment softening microfiltration membrane device for softening and turbidity-removing pretreatment of the high-concentration brine;

(2) Transport the high-concentration brine after softening and removing turbidity in step (1) to the nanofiltration membrane separation device, and use the separation characteristics of the nanofiltration membrane to separate the chemical oxygen demand (COD) and divalent salts in the high-concentration brine Separated from the monovalent salt to form a concentrated solution mainly composed of chemical oxygen demand (COD) and divalent salt and a permeate mainly composed of monovalent salt and trace chemical oxygen demand (COD);

(3) Send the permeate separated by nanofiltration in step (2) to the concentrated brine desalination reverse osmosis membrane device, further remove the salts in the nanofiltration permeate, and form a reverse osmosis that meets the quality requirements of reused water Product water and reverse osmosis concentrated water with concentrated monovalent salt;

(4) Mix concentrated brine concentrated by desalination and reverse osmosis in step (3) with nanofiltration concentrated water to form high-concentrated brine with high chemical oxygen demand (COD) and high salt content, and send it to the super-concentrated membrane The device is further reduced and concentrated, and an energy recovery device is installed to reduce the energy consumption of the super-concentration device. After the high-concentration brine is concentrated and reduced by the super-concentration device, the super-concentrated brine is formed and continues to enter the evaporation crystallization process section. The super-concentrated product water after desalination Mixed with the reverse osmosis product water desalinated in step (3), the water quality meets the quality requirements of reused water;

(5) Transport the pretreated softened sludge formed in step (1) to the sludge dewatering unit. After pressure filtration and dehydration, the filtrate returns to step (1) to soften the microfiltration membrane device, improve the overall water recovery rate, and form The filter cake is disposed of as ordinary solid waste;

In the steps (1), (2), (3) and (4), the water for washing and chemical cleaning is self-produced by the device, and the periodically generated chemical cleaning discharge water is recycled to the pretreatment unit to improve the overall water utilization rate.

In the step (1), only a softener is added to the coagulation reaction, and no coagulant and coagulant aid are added.

The nanofiltration membrane separation device in the step (2) is selected from a nanofiltration membrane module suitable for miscellaneous salt separation and high COD tolerance, and through multi-stage series connection, the recovery rate of the nanofiltration membrane separation device is improved, and the design recovery rate is ≥90 %.

The concentrated brine desalination reverse osmosis membrane device in the step (3) adopts a concentrated brine desalination membrane module suitable for monovalent salt concentration, and through multi-stage series connection, the recovery rate of the concentrated brine desalination reverse osmosis device is improved, and the design recovery rate is ≥ 80 %.

The super-concentration membrane device in the step (4) adopts super-concentration membrane modules suitable for the super-concentration process of high-concentration brine, which can simultaneously meet the requirements of high chemical oxygen demand (COD) pollution and high salt content concentration conditions , The design recovery rate is ≥ 45%, the salt content of the concentrated water in the super-concentration device reaches more than 10%, and the energy recovery rate device is used to effectively reduce the energy consumption of operation.

The present invention also provides a kind of thick brine zero-discharge membrane concentration equipment, comprising: softening microfiltration device, nanofiltration membrane separation device, concentrated brine desalination reverse osmosis membrane device, super concentration device, evaporation crystallization device, recycling water tank, its features The front end of the softening microfiltration device is provided with a reaction concentration tank, the reaction concentration tank is provided with a softening agent adding device, the water outlet of the reaction concentration tank is connected with the water inlet of the softening microfiltration device, and the water outlet of the softening microfiltration device is connected to the nanofiltration device. The water inlet of the filter membrane separation device is connected, and a pH value adjustment mechanism is installed in front of the water outlet of the softening microfiltration device. The water outlet of the membrane device is connected to the water inlet of the super-concentration device, the water outlet of the super-concentration device is connected to the recycling water tank, and the super-concentrated brine outlet of the super-concentration device is connected to the evaporation and crystallization device.

The nanofiltration membrane of the nanofiltration membrane separation device is a nanofiltration membrane module suitable for miscellaneous salt separation and high COD tolerance, and has a multi-stage series structure.

The concentrated brine desalination reverse osmosis membrane device is a concentrated brine desalination membrane module suitable for monovalent salt concentration, and is connected in series through multiple stages.

The softening microfiltration membrane device adopts an organic tubular microfiltration membrane, and the filtration accuracy is less than 0.1 micron.

The invention has the advantages of effectively improving the efficiency of equipment for treating concentrated brine through the combination of multiple concentration processes, achieving the goals of reduction and zero discharge of concentrated brine, and reducing the operating cost of concentrated brine treatment equipment.

Description of drawings

Figure 1 Block diagram of concentrated brine zero discharge membrane concentration process;

Fig. 2 is a structural schematic diagram of the present invention.

In the figure: 1 reaction concentration tank, 2 softening microfiltration device, 3 nanofiltration membrane separation device, 4 concentrated brine desalination reverse osmosis membrane device, 5 super concentration device, 6 evaporation crystallization device, 7 recycling water tank;

Pretreatment section: 101 storage adjustment tank, 102 advanced oxidation device, 103 reaction concentration tank, 104 softening microfiltration device, 105 intermediate pool, 106 sludge dehydration unit, 107 adjustment tank lift pump, 108 microfiltration membrane suction pump, 110 Strong oxidant dosing device, 111 softening agent dosing device;

Membrane concentration section: 201 security filter, 202 nanofiltration membrane separation device, 203 nanofiltration outlet tank, 204 security filter, 205 concentrated brine desalination reverse osmosis device, 206 reverse osmosis concentrated water tank, 207 membrane softening device, 208 super concentration inlet Water tank, 209 ultra-concentration device, 210 reuse water tank, 211 ultrafiltration inlet pump, 212 reverse osmosis inlet pump, 213 reverse osmosis high-pressure pump, 214 membrane softening feed pump, 215 ultra-concentration feed pump, 216 ultra-concentration high-pressure pump, 217 Ultrafiltration device cleaning pump, 219 Air compressor, 220 Chemical cleaning device, 221 Sodium hypochlorite dosing device, 222 Softener dosing device, 223 Antiscalant dosing device, 224 Citric acid dosing device; 230 Evaporation crystallization device.

detailed description

Embodiments of the present invention are further described below in conjunction with the accompanying drawings:

Embodiment one:

Concentrated brine enters the reaction concentration tank 1 of the softening microfiltration membrane device 2 in the pretreatment step, (see Figure 1) enters the softening microfiltration membrane device 2 after fully coagulating and softening reaction after adding softeners such as lime in the reaction concentration tank 1 Perform filtration to remove hardness and turbidity, and remove most of the calcium and magnesium, hardness, alkalinity and suspended impurities in the concentrated brine; the inorganic sludge discharged from the softening microfiltration membrane device for 2 cycles is dewatered by pressure filtration, and the filtrate is returned to the reaction concentration tank 1. The dehydrated cake is formed into ordinary sludge and solid waste, which is transported outside for disposal. After the pH of the softened microfiltration membrane device 2 is adjusted back, it enters the nanofiltration membrane separation device 3; the concentrated brine is separated and concentrated by the nanofiltration membrane separation device 3 to form a sodium sulfate And most of the nanofiltration concentrated water of COD and the nanofiltration product water mainly containing sodium nitrate, sodium chloride, and trace COD; The produced water meets the reuse requirements and enters the reuse water tank 7. The high-concentration brine formed by reverse osmosis concentration is mixed with nanofiltration concentrated water and enters the super-concentration device 5 for further desalination and concentration. The water produced by the super-concentration membrane after further desalination meets the reuse requirements Afterwards, it enters the reuse water tank 7, which is used for rehydration of circulating water in the factory area, and the super-concentrated brine formed by super-concentration enters the subsequent evaporation and crystallization device 6. The solid-liquid separation is completed by the evaporative crystallization device 6 .

The water used for periodic dispensing and cleaning of microfiltration, nanofiltration, reverse osmosis, and ultra-concentrated membranes in the device uses the self-produced water of the device, and the cleaning discharge water returns to the reaction concentration tank 1 of the softening microfiltration membrane device 2.

The technique of the present embodiment comprises the following steps:

(1) Transport the high-concentration brine to the pretreatment softening microfiltration membrane device for softening and turbidity-removing pretreatment of the high-concentration brine;

(2) Transport the high-concentration brine after softening and deturbidity in step (1) to the nanofiltration membrane separation device, and use the separation characteristics of the nanofiltration membrane to separate COD, divalent salt and monovalent salt in the high-concentration brine, Separately form the concentrated solution with COD and divalent salt as the main body and the permeate with monovalent salt and trace COD as the main body;

(3) Send the permeate separated by nanofiltration in step (2) to the concentrated brine desalination reverse osmosis membrane device, further remove the salts in the nanofiltration permeate, and form a reverse osmosis that meets the quality requirements of reused water Product water and reverse osmosis concentrated water with concentrated monovalent salt;

(4) Mix the concentrated brine concentrated by desalination and reverse osmosis in step (3) with nanofiltration concentrated water to form high-concentration brine with high COD and high salt content, and transport it to the super-concentration membrane device for further reduction and concentration. An energy recovery device is also installed to reduce the energy consumption of the super-concentration device. After the high-concentration brine is concentrated and reduced by the super-concentration device, the super-concentrated brine is formed and continues to enter the evaporation and crystallization process section. The reverse osmosis produced water with desalination is mixed, and the water quality meets the quality requirements of reused water;

(5) Transport the pretreated softened sludge formed in step (1) to the sludge dewatering unit. After pressure filtration and dehydration, the filtrate returns to step (1) to soften the microfiltration membrane device, improve the overall water recovery rate, and form The filter cake is disposed of as ordinary solid waste;

In the above steps (1) (2) (3) (4), the water used for washing and chemical cleaning is self-produced by the device, and the periodically generated chemical cleaning discharge water is recycled to the pretreatment unit to improve the overall water utilization rate.

After the solid-liquid centrifugal separation in step (2), the concentrated brine is transported to the nanofiltration membrane device. The tolerance to COD of the nanofiltration membrane module is much higher than that of ordinary reverse osmosis and the monovalent salt and divalent salt in the water body. According to the selective permeation characteristics, nanofiltration is used to pre-concentrate and separate the pretreated concentrated brine to form a concentrated solution mainly composed of COD and divalent salts and a permeate mainly composed of monovalent salts and trace COD.

The permeate produced by nanofiltration separation in step (3) mainly contains monovalent salt and microfiltration COD, so concentrated brine desalination membrane device can be used for re-concentration and reuse, and the quality of desalination water can meet the national "Urban Sewage Recycling and Utilization of Industrial Water" Water Quality (GB/T 19923-2005) refers to the water quality standard for reclaimed water used as supplementary water for open circulating cooling water. The concentration side forms high-concentration brine with a salt content of about 5%.

After the high-concentration brine formed in steps (3) and (4) is mixed, the COD reaches about 1000 mg/L, and the salt content reaches about 6%. Conventional reverse osmosis membrane modules cannot continue to concentrate, so the use can meet the high COD tolerance at the same time and high-salt-content working conditions for super-concentration of the super-concentration membrane module, the high-concentration brine formed in steps (3) and (4) is further concentrated and reduced, so that the salt content of the concentrated brine reaches more than 10%, and the COD reaches 2000mg/L above. Since in order to overcome the extremely high osmotic pressure, it needs to be higher than the operating pressure of conventional concentrated brine desalination reverse osmosis, and the operating energy consumption is relatively high. The energy recovery device is used to effectively reduce the operating energy consumption of the super-concentration device. The water produced by the super-concentration unit is mixed with the water produced by the front-stage concentrated brine desalination and reverse osmosis unit, and the water quality meets the national "Urban Sewage Reuse and Utilization of Industrial Water Quality" (GB/T 19923-2005) regarding the use of recycled water as supplementary water for open circulating cooling water. water quality standards.

Take the concentrated brine to be treated in a typical coal chemical zero discharge plant as an example. The influent water volume is 60m ³ /h, the salt content is 1.7%, the COD is 300mg/L, the total hardness is 1000mg/L, and the total alkalinity is 2000mg/L. After this membrane concentration process After reduction and reuse, the water volume of ultra-concentrated brine will be less than 10m ³ /h, and the overall operating cost will be less than 7 yuan/m ³ . In the pretreatment section, the concentrated brine is stored in the storage adjustment tank 101 for water quality and quantity adjustment, and the outlet of the storage adjustment tank is connected to the water inlet of the advanced oxidation device 102 through a pipeline and a lift pump 107 of the adjustment tank; Adding device 110, throws strengthened oxidizing agent to carry out oxidation; The outlet of advanced oxidation device 102 is connected to reaction concentration tank 103 by pipeline, and reaction concentration tank 103 is provided with softening agent dosing device 111, adds softening agent, makes the calcium magnesium plasma in water produce The precipitate is removed in the subsequent process; the outlet of the reaction concentration tank 103 is connected to the softening microfiltration device 104 through a pipeline; metal flocs such as calcium carbonate and magnesium hydroxide are removed through microfiltration membrane filtration in the softening microfiltration device 104; The outlet water of the microfiltration device 104 enters the intermediate pool 105 through the pipeline and the microfiltration membrane suction pump 108, and the outlet of the intermediate pool 105 is connected to the membrane concentration section through the pipeline. The sediment in the softening microfiltration device 104 is pumped through the sludge outlet to the sludge treatment unit 106 for treatment.

In the membrane concentration section, the outlet of the intermediate pool 106 in the pretreatment section is connected to the security filter 201 through the pipeline and the nanofiltration inlet pump 211, and a scale inhibitor dosing device 223 is provided in front of the security filter 201 for adding Scale inhibitor; the water outlet of the security filter 201 is connected to the water inlet of the nanofiltration membrane separation device 202 through a pipeline. Connected to the nanofiltration outlet tank 203; the nanofiltration membrane separation device 202 is provided with a chemical cleaning device 220, which is used to clean the ultrafiltration membrane when the membrane is seriously polluted, and the cleaning liquid is returned to the chemical cleaning device 220 to be reused. The cleaning liquid is discharged outside; one water outlet of the nanofiltration water outlet tank 203 is connected with the water inlet of the security filter 204 through a pipeline and a reverse osmosis water inlet pump 212, and the other water outlet is connected with the nanofiltration membrane separation device cleaning pump 217 through a pipeline and a nanofiltration membrane separation device. The cleaning port of the membrane separation device 202 is connected, and the pipeline is provided with a sodium hypochlorite dosing device 221 and a citric acid dosing device 224, which can perform daily cleaning on the nanofiltration membrane, and the concentrated water generated by the nanofiltration membrane separation device 202 enters the reverse osmosis Concentrated water tank 206; the outlet of security filter 204 is connected with the water inlet of concentrated brine desalination reverse osmosis device 205 through pipeline and reverse osmosis high-pressure pump 213, after water is separated by reverse osmosis membrane, the salt in the waste water can be concentrated into concentrated water, The concentrated brine desalination reverse osmosis device is equipped with a scale inhibitor dosing device 223, which can be added to slow down membrane scaling; the reverse osmosis produced water is desalinated water, and the clean water port of the reverse osmosis device 205 is connected to the return water through a pipeline. Water tank 210, concentrated water is then connected to reverse osmosis concentrated water tank 206 through pipeline; Chemical cleaning is possible. The reverse osmosis concentrated water tank 206 is equipped with a softener dosing device 222, which can add softening agents to form precipitates from the calcium and magnesium plasma in the concentrated water; Device 207, in the membrane softening device, precipitates such as calcium and magnesium are separated and removed. The water outlet of membrane softening device 207 enters super-concentrated water inlet tank 208 through pipeline, and the water outlet of super-concentrated water inlet tank 208 links to each other with security filter 204 by pipeline and super-concentrated feed pump 215, and security filter 204 water outlets pass pipeline and ultra-concentrated Concentration high-pressure pump 216 is connected with the water inlet of super-concentration device 209, and super-concentration device 209 is a high-pressure reverse osmosis roll-type membrane. In super-concentration device, the salt in concentrated water is further concentrated through membrane separation; The clear water port of the super-concentration device enters the reuse water tank 210 through a pipeline, and the dope produced by the super-concentration device 209 is connected to the evaporation and crystallization device 230 through a pipeline. The super concentration device 209 is cleaned with a chemical cleaning device 220, which can be used for chemical cleaning when the membrane is polluted.

During the above operations, the following parameters should be controlled carefully:

Pretreatment section: the residence time of the storage adjustment tank 101, the dosage and pH of the strong oxidation dosing device 110, the dosage and pH of the softening agent in the reaction concentration tank 103, the concentration of suspended solids, and the membrane softening of the microfiltration device 104 Flux, membrane area and turbidity, SDI and hardness of effluent.

Membrane concentration section: membrane flux of nanofiltration membrane separation device 202, membrane flux of concentrated brine desalination reverse osmosis device 205, membrane flux of membrane softening device 207, dosage of softening agent in reverse osmosis concentrated water tank 206, The membrane flux of the super-concentration device 209, the membrane flux of the above-mentioned various membranes will have different values with different raw water qualities. It is also necessary to control the conductivity of the effluent from each section of the membrane. In addition, the types and dosages of various membrane chemical cleaning agents, cleaning frequency, etc. also change with the change of raw water. The evaporation capacity, operating temperature and pressure of the evaporative crystallization device 230.

Embodiment two:

This embodiment is the same as Embodiment 1, except that the advanced oxidation can be ozone oxidation (or ozone catalytic oxidation, ozone hydrogen peroxide oxidation). The super concentration device 209 can be a vibrating membrane, a high pressure membrane or a forward osmosis membrane. The softening microfiltration membrane device 104 can be precipitation + immersion micro (ultra) filtration, or precipitation + tubular micro (ultra) filtration, or can be a traditional chemical softening process, that is, drug addition reaction + precipitation + filtration + ultrafiltration. The evaporative crystallizer 230 can be multi-effect evaporative concentration or mechanical compression evaporative concentration. The nanofiltration membrane separation device 202 can be changed to a weak acid cation exchange, and the supporting auxiliary equipment of the nanofiltration system can be changed to an ion exchange supporting system, and the membrane softening device 207 and its supporting equipment in the membrane treatment section are omitted.

Embodiment three:

This embodiment is the same as Embodiment 1, except that when the hardness of the raw water is low, the membrane softening device 207 in the membrane treatment process can be omitted.

Claims (10)

1. A zero-discharge membrane concentration process for concentrated brine, the process features comprising the following steps: (1) Transport the high-concentration brine to the pretreatment softening microfiltration membrane device to perform softening and turbidity-removing pretreatment on the high-concentration brine; (2) Transport the high-concentration brine after softening and turbidity pretreatment in step (1) to the nanofiltration membrane separation device, and use the separation characteristics of the nanofiltration membrane to separate the chemical oxygen demand, divalent salt and The monovalent salt is separated to form a concentrated solution mainly composed of chemical oxygen demand and divalent salt and a permeate mainly composed of monovalent salt and trace chemical oxygen demand; (3) Send the permeate separated by nanofiltration in step (2) to the concentrated brine desalination reverse osmosis membrane device, further remove the salts in the nanofiltration permeate, and form a reverse osmosis that meets the quality requirements of reused water Product water and reverse osmosis concentrated water with concentrated monovalent salt; (4) The concentrated brine desalinated and concentrated by reverse osmosis in step (3) is mixed with nanofiltration concentrated water to form high-concentrated brine with high chemical oxygen demand and high salt content, which is sent to the super-concentrated membrane device for further reduction. The concentrated brine is concentrated and reduced by the super-concentration device to form super-concentrated brine and then enters the evaporation and crystallization process section. The super-concentrated water after desalination is mixed with the reverse osmosis product water that has been desalted in step (3). Meet the quality requirements of reused water; (5) Transport the pretreated softened sludge formed in step (1) to the sludge dewatering unit. After pressure filtration and dehydration, the filtrate returns to step (1) to soften the microfiltration membrane device, improve the overall water recovery rate, and form The filter cake is disposed of as ordinary solid waste. 2. The concentrated brine zero-discharge membrane concentration process according to claim 1, characterized in that in the steps (1) (2) (3) (4), the water used for flushing and chemical cleaning uses the self-produced water of the device, periodically The resulting chemical cleaning effluent is recycled to the pretreatment unit. 3. The concentrated brine zero-discharge membrane concentration process according to claim 1, characterized in that in the step (1), only a softener is added to the coagulation reaction, and no coagulant and coagulant are added. 4. The concentrated brine zero-discharge membrane concentration process according to claim 1, characterized in that the nanofiltration membrane separation device in the step (2) is selected to be suitable for the separation of miscellaneous salts and to withstand high chemical oxygen demand. Membrane modules, and through multi-stage series connection, improve the recovery rate of the nanofiltration membrane separation device, and the design recovery rate is ≥90%. 5. The concentrated brine zero-discharge membrane concentration process according to claim 1, characterized in that the concentrated brine desalination reverse osmosis membrane device in the step (3) adopts a concentrated brine desalination membrane module suitable for monovalent salt concentration, and Through multi-stage series connection, the recovery rate of the concentrated brine desalination reverse osmosis device is improved, and the design recovery rate is ≥ 80%. 6. The concentrated brine zero-discharge membrane concentration process according to claim 1 is characterized in that the super-concentration membrane device in the step (4) adopts a super-concentration membrane module suitable for a high-concentration brine super-concentration process, which can simultaneously meet Tolerant to high COD pollution and high salt content concentration conditions, the design recovery rate is ≥ 45%, and the salt content of the concentrated water of the super concentration device reaches more than 10%. 7. A concentrated brine zero-discharge membrane concentration equipment, comprising: softening microfiltration device, nanofiltration membrane separation device, reverse osmosis membrane device for desalination of concentrated brine, super concentration device, evaporation crystallization device, and water reuse tank, characterized in that The front end of the softening microfiltration device is equipped with a reaction concentration tank, and the reaction concentration tank is equipped with a softener dosing device. The water outlet of the reaction concentration tank is connected to the water inlet of the softening microfiltration device, and the water outlet of the softening microfiltration device is separated from the nanofiltration membrane. The water inlet of the device is connected, and the water outlet of the softening microfiltration device is equipped with a pH value adjustment mechanism. The water outlet is connected to the water inlet of the super-concentration device, the water outlet of the super-concentration device is connected to the recycling water tank, and the super-concentrated brine outlet of the super-concentration device is connected to the evaporation and crystallization device. 8. The zero-discharge membrane concentration equipment for concentrated brine according to claim 7, characterized in that the softening microfiltration membrane device adopts an organic tubular microfiltration membrane, and the filtration accuracy is less than 0.1 micron. 9. The concentrated brine zero-discharge membrane concentration equipment according to claim 7, characterized in that the nanofiltration membrane of the nanofiltration membrane separation device is a nanofiltration membrane module suitable for miscellaneous salt separation and high chemical oxygen demand tolerance , is a multi-segment series structure. 10. The concentrated brine zero-discharge membrane concentration equipment according to claim 7, characterized in that the concentrated brine desalination reverse osmosis membrane device is a concentrated brine desalination membrane module suitable for monovalent salt concentration, and is connected in series through multiple stages.