CN205603386U - Strong brine zero release membrane concentrator - Google Patents

Abstract

The utility model provides a strong brine zero release membrane concentrator, includes: soften the micro -filtration device, receive and strain membrane separation device, strong brine desalination reverse osmosis membrane device, hyperconcetration device, evaporation crystallization device. Soften the concentrated groove of the reaction delivery port of micro -filtration device and be connected with soft micro -filtration device water inlet, be equipped with pH value adjustment mechanism before the delivery port of soft micro -filtration device, the soft micro -filtration device and water inlet and the delivery port tandem connection of each other of straining membrane separation device, strong brine desalination reverse osmosis membrane device, hyperconcetration device, retrieval and utilization water tank, each equipment of receiving, the super strong brine of hyperconcetration device exports and evaporates the crystallization device to be connected. The utility model discloses technology includes processing step, the concentrated processing step of membrane in advance. The utility model discloses the advantage is the combination through multiple concentrated technology, and effective improve equipment handles the efficiency of strong brine, realizes the minimizing of strong brine, the target of zero release, reduces the running cost of strong brine treatment facility.

Description

Concentrated brine zero discharge membrane concentration equipment

technical field

The utility model relates to a water treatment device, in particular to a concentrated salt water zero discharge membrane concentration device.

Background technique

Zero discharge of wastewater is the goal required by coal chemical industry, papermaking and other industrial industries, and an important link to achieve sustainable and stable development. In the whole process of zero discharge of wastewater treatment, the high investment and operating costs of evaporation and crystallization devices restrict 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 devices in the coal chemical industry and papermaking industry is mainly the concentrated brine produced by wastewater biochemical treatment, advanced oxidation, and double-membrane system of reclaimed water reused by the wastewater discharged from coal chemical plants and papermaking processes. COD (Chemical Oxygen Demand), high salt content, high hardness, high alkalinity and other characteristics make it impossible to directly use conventional reverse osmosis for further concentration and reuse. However, due to the large amount of water in general, it directly enters evaporation and crystallization for thermal concentration and crystallization. Investment and operating 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 purpose of the invention of the utility model is to provide a concentrated brine zero-discharge membrane concentration process and equipment for the defects in the prior art. The utility model effectively increases the concentration multiple of the concentrated brine through the combination of various processes, realizes the reduction of the concentrated brine, realizes the reduction of the scale of the evaporation and crystallization device, and reduces the overall operation cost.

The utility model comprises: a softening microfiltration device, a nanofiltration membrane separation device, a concentrated brine desalination reverse osmosis membrane device, an ultra-concentration device, an evaporation crystallization device, and a reuse water tank, and is characterized in that the front end of the softening microfiltration device is provided with a reaction concentration Tank, the reaction concentration tank is equipped with a softener dosing device, which only adds softener and does not need to add coagulant and coagulant aid. The water outlet of the reaction concentration tank is connected to the water inlet of the softening microfiltration device, the water outlet of the softening microfiltration device is connected to the water inlet of the nanofiltration membrane separation device, and a pH value adjustment mechanism is arranged before the water outlet of the softening microfiltration device. The membrane separation device selects nanofiltration membrane modules suitable for the separation of miscellaneous salts and can withstand high chemical oxygen demand (COD), 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 water outlet of the nanofiltration membrane separation device is connected to the water inlet of the concentrated brine desalination reverse osmosis membrane device, the water outlet of the concentrated brine desalination reverse osmosis membrane device is connected to the water inlet of the super concentration device, and the concentrated brine desalination reverse osmosis membrane device is suitable for Concentrated brine desalination membrane modules with monovalent salt concentrated, and through multi-stage series connection, improve the recovery rate of concentrated brine desalination concentrated brine desalination reverse osmosis device, and the design recovery rate is ≥ 80%. The water outlet of the super-concentration device is connected to the reuse water tank, and the super-concentrated brine outlet of the super-concentration device is connected to the evaporation and crystallization device. Separation of salt and solvent or further concentration and reduction are completed by evaporative crystallization device.

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

The nanofiltration membrane of the nanofiltration membrane separation device is a nanofiltration membrane module suitable for the separation of miscellaneous salts and resistant to high chemical oxygen demand (COD), 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 device is a softening microfiltration membrane device, wherein the softening microfiltration membrane adopts an organic tubular microfiltration membrane, and the filtration accuracy is less than 0.1 micron. Submerged microfiltration membranes are also available.

The nanofiltration membrane separation device can be replaced by a weak acid cation exchange device.

The utility model has the advantages of effectively improving the treatment effect of the concentrated brine through the combination of various concentration processes, realizing the reduction of the concentrated brine, reducing the scale of the evaporation and crystallization device, and reducing the overall operating cost.

Description of drawings

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

Fig. 2 is a structural schematic diagram of the utility model.

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; Treatment 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 lifting 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

Further illustrate the embodiment of the present utility model below in conjunction with accompanying drawing.

Embodiment one:

Concentrated brine enters the reaction concentration tank 1 of the softening microfiltration membrane device 2 in the pretreatment section. (See Figure 1) After adding lime and other softeners in the reaction concentration tank 1, it is fully softened and reacted, and then enters the softening microfiltration membrane device 2 for filtration. Remove hard and turbidity, remove most of the calcium and magnesium, hardness, alkalinity and suspended impurities in the concentrated brine; soften the inorganic sludge discharged from the microfiltration membrane device for 2 cycles and dewater it by pressure filtration, and return the filtrate to the reaction concentration tank 1, The dehydrated cake forms ordinary sludge and solid waste, which is transported to the outside for disposal; the pH of the effluent from the softening microfiltration membrane device 2 is adjusted back and then enters the nanofiltration membrane separation device 3; the concentrated brine is separated and concentrated by the nanofiltration membrane separation device 3 to form a Most of the nanofiltration concentrated water with COD and the nanofiltration product water mainly containing sodium nitrate, sodium chloride, and trace COD; After meeting the reuse requirements, it 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 after further desalination meets the reuse requirements and enters the recycling The water tank 7 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 self-produced water is used for the periodic dispensing and cleaning of microfiltration, nanofiltration, reverse osmosis, ultra-superconcentration, and crystallization devices in the device, and the cleaning discharge water is returned to the reaction concentration tank 1 of the softening microfiltration membrane device 2.

The technique of the present embodiment comprises the following steps:

(1) Conveying the high-concentration brine to the pretreatment softening microfiltration membrane device 2 for pretreatment of the high-concentration brine by softening and removing turbidity;

(2) Transport the high-concentration brine after softening and removing turbidity in step (1) to the nanofiltration membrane separation device 3, and use the separation characteristics of the nanofiltration membrane to separate COD, divalent salt and monovalent salt in the high-concentration brine , respectively forming a concentrated solution with COD and divalent salt as the main body and a permeate with monovalent salt and trace COD as the main body;

(3) Transport the permeate separated by nanofiltration in step (2) to the concentrated brine desalination reverse osmosis membrane device 4, further remove the salts in the nanofiltration permeate, and form a reverse osmosis membrane that meets the quality requirements of reused water. Permeate product water and concentrated reverse osmosis concentrated monovalent salt water;

(4) After mixing the concentrated water concentrated by desalination and reverse osmosis of concentrated brine in step (3) with nanofiltration concentrated water to form high-concentrated brine with higher COD and high salt content, it is transported to the super-concentration device 5 for further reduction and concentration, The high-concentration brine is concentrated and reduced by the super-concentration device 5 to form super-concentrated brine and continues to enter the evaporation and crystallization process section. water quality requirements;

(5) Transport the pretreated softened sludge formed in step (1) to the sludge dewatering unit, and after pressure filtration and dehydration, the filtrate returns to step (1) to soften the microfiltration membrane device 2, improve the overall water recovery rate, and press filtration The formed filter cake is disposed of as ordinary solid waste;

After steps (1)(2)(3)(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.

After the solid-liquid centrifugal separation in step (2), the concentrated brine is transported to the nanofiltration membrane separation device 3, and the tolerance of the nanofiltration membrane module to COD is much higher than that of ordinary reverse osmosis and the monovalent salt, bivalent salt in the water body. Based on the selective permeation characteristics of valent salts, 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 salts and a small amount of COD. Therefore, concentrated brine desalination membrane devices can be used for re-concentration and reuse, and the quality of desalination water can meet the national "urban sewage recycling industrial water quality 》(GB/T 19923-2005) Regarding 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 the super-concentration component of the high-salt-content working condition are super-concentrated, and 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 more than 2000mg/L . 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 device is mixed with the water produced by the concentrated brine desalination reverse osmosis device in the previous stage, and the water quality reaches the national "Urban Sewage Recycling and Utilization of Industrial Water Quality" (GB/T 19923-2005) on reclaimed water used as open circulating cooling water Water quality standards for make-up water.

Taking 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 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 .

Referring to Fig. 2, in the pretreatment section, the concentrated brine is stored in the storage regulating tank 101 to adjust the water quality and quantity, and the outlet of the storage regulating tank is connected with the water inlet of the advanced oxidation device 102 through the pipeline and the regulating tank lift pump 107; the advanced oxidation device 102 is set There is a strong oxidizing agent dosing device 110, which throws a strong oxidizing agent for oxidation; the water outlet of the advanced oxidizing device 102 is connected to the reaction concentration tank 103 through a pipeline, and the reaction concentration tank 103 is provided with a softening agent dosing device 111, and the softening agent is added to make the water Calcium and magnesium plasma production precipitates are removed in subsequent processes; the outlet of the reaction concentration tank 103 is connected to the softening microfiltration device 104 through pipelines; metal flocs such as calcium carbonate and magnesium hydroxide are filtered through the microfiltration membrane in the softening microfiltration device 104 be removed; the water outlet of the softening 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 quality. 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 (5)

1. 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 reuse water 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. 2. The concentrated brine zero-discharge membrane concentration equipment according to claim 1, characterized in that the softening microfiltration device is a softening microfiltration membrane device, wherein the softening microfiltration membrane adopts an organic tubular microfiltration membrane, and the filtration accuracy is less than 0.1 micron , or use submerged microfiltration membranes. 3. The concentrated brine zero-discharge membrane concentration equipment according to claim 1, 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 , and is a multi-segment series structure. 4. The concentrated brine zero-discharge membrane concentration equipment according to claim 1, 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. 5. The concentrated brine zero discharge membrane concentration equipment according to claim 1, characterized in that the nanofiltration membrane separation device is replaced by a weak acid cation exchange device.