CN113620491A - Resource utilization system and method for deacidification wastewater with high salt content - Google Patents

Resource utilization system and method for deacidification wastewater with high salt content Download PDF

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CN113620491A
CN113620491A CN202110806168.1A CN202110806168A CN113620491A CN 113620491 A CN113620491 A CN 113620491A CN 202110806168 A CN202110806168 A CN 202110806168A CN 113620491 A CN113620491 A CN 113620491A
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tank
nanofiltration
outlet
ultrafiltration
wastewater
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CN113620491B (en
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杨虎林
李磊
邓强
吴雯
马晓军
李超锋
厉兴平
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Zhejiang Environmental Protection Group Co ltd
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Zhejiang Environmental Protection Group Co ltd
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
    • C02F11/121—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering
    • C02F11/122—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering using filter presses
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/02—Treatment of water, waste water, or sewage by heating
    • C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/22—Treatment of water, waste water, or sewage by freezing
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/442—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by nanofiltration
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/101—Sulfur compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/12—Halogens or halogen-containing compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/12—Halogens or halogen-containing compounds
    • C02F2101/14—Fluorine or fluorine-containing compounds
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A20/00—Water conservation; Efficient water supply; Efficient water use
    • Y02A20/124—Water desalination
    • Y02A20/131—Reverse-osmosis

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  • Engineering & Computer Science (AREA)
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  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

The invention discloses a resource utilization system and a resource utilization method for deacidification wastewater with high salt content, wherein the system comprises a homogenizing tank, a first reaction tank, a second reaction tank, a sedimentation tank, a concentration tank, an ultrafiltration device, an ultrafiltration water-producing tank, a nanofiltration device, a nanofiltration water-producing tank, a reverse osmosis device, a triple-effect evaporation unit, a nanofiltration concentrated solution tank and a freezing crystallization device which are sequentially connected; CaCl is arranged above the first reaction tank2A chemical adding device, Na is arranged above the second reaction tank2CO3A hydrochloric acid dosing device is arranged above the dosing device and the ultrafiltration water producing pool. The invention relates to aThrough the cooperation of medicament reaction and membrane treatment devices with different levels of precision, SO in the deacidification wastewater can be treated4 2‑And Cl‑Effective separation is carried out to finally obtain the Na with higher purity2SO4And NaCl, so that effective recovery and resource utilization of salts in the deacidification wastewater can be realized, the generation amount of solid waste is reduced, and the energy-saving and emission-reducing degree is improved.

Description

Resource utilization system and method for deacidification wastewater with high salt content
Technical Field
The invention relates to the technical field of deacidification wastewater resource utilization, in particular to a high-salt-content deacidification wastewater resource utilization system and a method.
Background
The incineration technology is one of effective treatment technologies of urban domestic garbage and hazardous waste, and with the increasing strictness of flue gas emission indexes, the wet deacidification technology is an effective guarantee means for standard emission of the incineration flue gas at present, but the wet deacidification technology can generate acid wastewater with complex composition and high salt content, and the effective treatment of the deacidification wastewater becomes one of the key points and difficulties of zero emission of the wastewater of a garbage incineration plant.
At present, the deacidification wastewater treatment method mainly adopts a physical and chemical treatment process to remove impurities and salt in the wastewater, so that the treated effluent meets the discharge standard. For example, chinese patent publication No. CN108439651A discloses a "method and system for treating wet deacidification wastewater", the method includes: s1, pretreating the wet deacidification wastewater, and oxidizing the reducing substances in the wet deacidification wastewater; s2, performing primary flocculation precipitation treatment on the pretreated wet deacidification wastewater to remove calcium, magnesium and silicate in the pretreated wet deacidification wastewater; s3, performing secondary flocculation and precipitation treatment on the supernatant obtained by the primary flocculation and precipitation treatment to remove heavy metal ions in the supernatant; s4, adjusting the pH value of the supernatant obtained by the secondary flocculation precipitation treatment; s5, performing primary filtration on the supernatant after pH value adjustment to carry out interception and separation; and S6, performing secondary filtration on the filtrate obtained after the primary filtration.
However, after the deacidification wastewater is treated by using the method in the prior art, the salt recovered from the deacidification wastewater is mixed salt of various components, cannot be recycled and can only be transported and treated as solid waste, the comprehensive treatment cost of the waste salt is very high, and the requirements of energy conservation and emission reduction can not be met.
Disclosure of Invention
The invention provides a high-salt-content deacidification wastewater resource utilization system and method, aiming at overcoming the problems that after deacidification wastewater is treated by adopting a method in the prior art, salt recovered from the deacidification wastewater is mixed salt of various components, resource recycling treatment cannot be carried out, the salt can only be used for outward transportation of solid waste, and the comprehensive treatment cost of the waste salt is very high, and the SO in the deacidification wastewater can be utilized through the cooperation of medicament reaction and membrane treatment devices with different precision at each stage4 2-And Cl-Effective separation is carried out, and finally, Na which has higher purity and can be directly recycled is obtained2SO4And NaCl, so that effective recovery and resource utilization of salts in the deacidification wastewater can be realized, the generation amount of solid waste is reduced, and the energy-saving and emission-reducing degree is improved.
In order to achieve the purpose, the invention adopts the following technical scheme:
a resource utilization system for deacidification wastewater with high salt content comprises a homogenizing tank, a first reaction tank, a second reaction tank, a sedimentation tank, a concentration tank, an ultrafiltration device, an ultrafiltration water production tank, a nanofiltration device, a nanofiltration water production tank, a reverse osmosis device, a triple-effect evaporation unit, a nanofiltration concentrated solution tank and a freezing crystallization device which are sequentially connected with each other; CaCl is arranged above the first reaction tank2A chemical adding device, Na is arranged above the second reaction tank2CO3A hydrochloric acid dosing device is arranged above the dosing device and the ultrafiltration water producing pool.
The invention also provides a method for resource utilization of the high-salt-content deacidification wastewater by using the system, which comprises the following steps:
(1) the deacidification wastewater enters a first reaction tank after being homogenized by a homogenizing tank, and CaCl is added2Carrying out reaction;
(2) first reactionThe effluent of the pool enters a second reaction pool, and Na is added2CO3Carrying out reaction;
(3) after the effluent of the second reaction tank sequentially passes through a sedimentation tank and a concentration tank for sedimentation, the supernatant enters an ultrafiltration system for ultrafiltration;
(4) the permeate after ultrafiltration enters an ultrafiltration water producing tank, and hydrochloric acid is added for reaction;
(5) the effluent of the ultrafiltration water production tank enters a nanofiltration device for nanofiltration, the nanofiltration concentrated solution enters a freezing crystallization device, and Na is obtained by recycling after freezing crystallization2SO4；
(6) The permeate after nanofiltration enters a reverse osmosis device for reverse osmosis through a nanofiltration water production pool;
(7) and (4) the concentrated solution after reverse osmosis enters a triple-effect evaporation unit, and NaCl is obtained after evaporation and recovery.
In deacidification wastewater generated by waste incineration, the main component is sodium chloride as the main component and is mixed with ions such as fluoride ions, sulfate radicals, carbonate radicals and bicarbonate radicals, suspended matters such as calcium sulfate and the like in the deacidification wastewater are removed through a homogenizing tank, and unnecessary influence of the suspended matters on a subsequent device is avoided; then passes through the first reaction tank and CaCl2CaCl is added into wastewater by a medicine adding device2Make most of F in water-And CO3 2-With Ca2+The calcium fluoride and the calcium carbonate precipitate are generated by the reaction to remove F-And CO3 2-The object of (a); the effluent enters a second reaction tank and passes through Na2CO3Adding Na into the wastewater by a medicine adding device2CO3Most of metal ions (such as calcium, magnesium, barium, strontium, iron, manganese and the like) and CO in the wastewater3 2-Carbonate precipitate is generated by reaction, so as to achieve the purpose of primarily removing metal ions; because a large amount of suspended matters are formed in the first reaction tank and the second reaction tank, the effluent of the second reaction tank firstly enters a sedimentation tank, large-particle suspended matters in the water are removed in a gravity sedimentation mode, and the supernatant enters a concentration tank to further remove the suspended matters in the wastewater; the supernatant of the concentration tank enters an ultrafiltration device, and suspended matters which cannot be precipitated in the wastewater are finally treated by an ultrafiltration membraneRemoving; the permeate after ultrafiltration enters an ultrafiltration water production tank, hydrochloric acid is added into the ultrafiltration water production through a hydrochloric acid dosing device, the pH of the wastewater is adjusted, and HCO in the wastewater is removed3 -(ii) a The wastewater after the pH adjustment enters a nanofiltration device, and SO is added under the action of a nanofiltration membrane4 2-With Cl-Separating and enriching SO4 2-The nanofiltration concentrated solution enters a nanofiltration concentrated solution pool, and then is frozen and crystallized by a freezing and crystallizing device to obtain Na2SO4(ii) a Rich in Cl-And (3) the nanofiltration permeate enters a nanofiltration water production tank, then continues to enter a reverse osmosis device for reverse osmosis treatment, NaCl and water are separated, the separated effluent can be recycled or directly discharged, the NaCl-rich concentrated solution obtained after separation enters a triple effect evaporation unit, and the NaCl with higher purity can be recovered after evaporation.
Therefore, the invention can mix the SO in the deacidification wastewater with the membrane treatment device with different precision at each stage through the reagent reaction4 2-And Cl-Effective separation is carried out, the purity of the NaCl finally obtained by recovery can reach 96.9-98.2%, and the NaCl meets the physical and chemical index requirements of industrial salt standard, namely Na2SO4The purity can reach 92.8-94.6%, and the physical and chemical index requirements of anhydrous sodium sulfate standards are met; therefore, the effective recovery and resource utilization of salts in the deacidification wastewater can be realized, the generation amount of solid waste is reduced, and the energy-saving and emission-reducing degree is improved.
Preferably, a defluorination reactor is arranged between the ultrafiltration water production tank and the nanofiltration device, and defluorination resin is arranged in the defluorination reactor. A defluorination reactor is arranged in front of the nanofiltration device, and F in the wastewater can be treated by defluorination resin-Further adsorption removal is carried out, thereby improving the Na finally obtained2SO4And the concentration of NaCl.
Preferably, a sludge pool and a filter press which are connected are also arranged in the system; the sludge tank is provided with a sludge inlet, a sludge outlet and a wastewater outlet; the bottoms of the sedimentation tank and the concentration tank are provided with sludge hoppers; the sludge inlet of the sludge tank is respectively connected with the sludge buckets of the sedimentation tank and the concentration tank, the sludge outlet of the sludge tank is connected with the filter press, and the wastewater outlet of the sludge tank is connected with the water inlet of the first reaction tank. The system is internally provided with the sludge tank and the filter press, so that the sludge generated in the sedimentation tank and the concentration tank can be recovered and dehydrated, and the subsequent transportation and disposal of the sludge are facilitated; the supernatant liquid of the sludge tank can flow back to the first reaction tank for retreatment.
Preferably, a tubular ultrafiltration membrane component is arranged in the ultrafiltration device; the ultrafiltration device is provided with an ultrafiltration device water inlet, an ultrafiltration device permeate outlet and an ultrafiltration device concentrate outlet, the ultrafiltration device water inlet is connected with the water outlet of the concentration tank, the ultrafiltration device permeate outlet is connected with the ultrafiltration water production tank, and the ultrafiltration device concentrate outlet is connected with the water inlet of the concentration tank. And (4) allowing the permeate of the wastewater after passing through the ultrafiltration device to enter a subsequent treatment device for subsequent treatment, and allowing the concentrated solution to flow back to the concentration tank for precipitation treatment again.
Preferably, the nanofiltration device comprises a primary nanofiltration device and a secondary nanofiltration device, wherein nanofiltration membrane components are arranged in the primary nanofiltration device and the secondary nanofiltration device, and a water inlet, a permeate outlet and a concentrated solution outlet are respectively arranged on the primary nanofiltration device and the secondary nanofiltration device; the water inlet of the primary nanofiltration device is connected with the defluorination reactor, the permeate outlet of the primary nanofiltration device is connected with the water inlet of the secondary nanofiltration device, and the concentrated solution outlet of the primary nanofiltration device is connected with the nanofiltration concentrated solution tank; and a permeate outlet of the second-stage nanofiltration device is connected with the nanofiltration water production tank, and a concentrate outlet of the second-stage nanofiltration device is connected with a water inlet of the first-stage nanofiltration device. The system is provided with the two-stage nanofiltration device, SO that SO is fully ensured4 2-With Cl-The separation effect of (2) thus improving the purity of NaCl crystal salt obtained after triple effect evaporation and facilitating the subsequent recycling of NaCl.
Preferably, the preparation method of the nanofiltration membrane used in the nanofiltration membrane component comprises the following steps:
A) ZrCl with the molar ratio of 1: 1-24And 2-amino terephthalic acid are dissolved in DMF, hydrochloric acid is added, ultrasonic dispersion is carried out for 20-30 min, then the mixture is heated to 120-140 ℃, hydrothermal reaction is carried out for 24-36 h, the product is cooled to room temperature, and then the product is filtered, cleaned and dried to obtain the productTo metal organic framework materials; wherein the mass concentration of the added hydrochloric acid is 35-37%, and the volume ratio of the added hydrochloric acid to DMF is 1: 50-60; firstly, the step A) is carried out, and ZrCl is adopted4Is a metal source, and 2-amino terephthalic acid is an organic ligand to prepare a metal organic framework material with amino;
B) adding a metal organic framework material and N-methylimidazole into ethanol, and stirring for 12-18 h under the protection of nitrogen; then adding 3-bromopropylamine hydrobromide, and carrying out reflux reaction for 24-36 h under the protection of nitrogen; wherein the mass ratio of the metal organic framework material to the N-methylimidazole to the 3-bromopropylamine hydrobromide is 2-2.5: 1: 2.9-2.95; filtering the product, washing with ethanol, and drying in vacuum to obtain an ionic liquid modified metal organic framework material; in the step B), N-methylimidazole is adsorbed and diffused into a frame structure of the metal organic frame material, then 3-bromopropylamine hydrobromide is adsorbed and diffused into the frame structure to react with N-methylimidazole, so that ionic liquid 1- (3-aminopropyl) -3-methylimidazole bromide is generated, and the ionic liquid is loaded in the frame structure of the metal organic frame material, and the ionic liquid modified metal organic frame material is obtained;
C) dissolving piperazine in deionized water, adding an ionic liquid modified metal organic framework material, uniformly dispersing, and adjusting the pH value of the solution to 5-7 to obtain an aqueous phase solution, wherein the mass concentration of piperazine in the aqueous phase solution is 0.2-0.4%, and the mass ratio of piperazine to the metal organic framework material is 2-4: 1;
D) adding trimesoyl chloride into ethylcyclohexane, and stirring and dissolving to obtain an oil phase solution with the mass concentration of the trimesoyl chloride of 0.1-0.2%;
E) immersing the porous polysulfone base membrane into the water phase solution for soaking for 5-10 min, taking out, and blowing the residual water phase solution on the base membrane to be clean until no water drops exist on the surface of the base membrane; then immersing the base film into the oil phase solution for contact reaction for 2-5 min; taking out the base membrane, pre-drying the base membrane at 50-70 ℃ for 1-2 min, then cleaning the base membrane with hot water at 70-90 ℃ for 4-6 min, soaking the base membrane in glycerol with the mass concentration of 7-9% for 1-3 min, taking out the base membrane, and drying the base membrane at 50-70 ℃ to obtain the nanofiltration membrane. In the steps D) to E), piperazine and trimesoyl chloride are subjected to interfacial polymerization reaction on the surface of the porous polysulfone base membrane to generate a polypiperazine amide functional layer, so that the nanofiltration membrane has good selective permeability and can separate divalent ions from monovalent ions. In the interfacial polymerization process, amino in the metal organic framework material can also participate in the reaction, so that the metal organic framework material can be firmly loaded in the polypiperazine amide functional layer and is not easy to fall off from the surface of the nanofiltration membrane.
At present, the commercialized nanofiltration membrane mainly comprises a polypiperazine amide composite nanofiltration membrane, and the existing nanofiltration membrane generally has low water flux, so that the water flux is seriously attenuated along with the prolonging of the service time, and Cl is influenced-And SO4 2-The separation effect of (1). Therefore, when the nanofiltration membrane is prepared, the metal organic framework material is added into the polypiperazine amide functional layer, and the water flux of the nanofiltration membrane can be effectively improved by utilizing the hollow porous structure of the metal organic framework material; however, the addition of the metal organic framework material can also cause the density of a polypiperazine amide functional layer generated in the interfacial polymerization process to be reduced, thereby influencing the SO of the nanofiltration membrane4 2-The invention modifies the ionic liquid in the porous structure of the metal organic framework material, and SO is treated by the ionic liquid4 2-The adsorption effect of the nano-filtration membrane on SO is improved4 2-The retention rate of the nano-filtration membrane is high, SO that the prepared nano-filtration membrane has high SO4 2-Retention rate and water flux, effective on Cl-And SO4 2-Separation is carried out.
Preferably, a reverse osmosis membrane assembly is arranged in the reverse osmosis device, and a reverse osmosis device water inlet, a reverse osmosis device permeate outlet and a reverse osmosis device concentrate outlet are formed in the reverse osmosis device; the water inlet of the reverse osmosis device is connected with the nanofiltration water production tank, and the concentrated solution outlet of the reverse osmosis device is connected with the triple-effect evaporation unit; the system is also internally provided with a reuse water tank connected with a permeate outlet of the reverse osmosis device.
Preferably, the triple-effect evaporation unit comprises a first effect evaporator, a second effect evaporator and a third effect evaporator which are sequentially connected, wherein the top parts of the first effect evaporator, the second effect evaporator and the third effect evaporator are respectively provided with a steam outlet, the middle parts of the first effect evaporator, the second effect evaporator and the third effect evaporator are respectively provided with a feed inlet and a steam inlet, and the bottom parts of the first effect evaporator, the second effect evaporator and the third effect evaporator are respectively provided with a condensed water outlet and a discharge outlet; the feed inlet of the first effect evaporator is connected with a concentrated solution outlet of the reverse osmosis device, and the discharge outlet and a steam outlet of the first effect evaporator are respectively connected with the feed inlet and a steam inlet of the second effect evaporator; and the discharge hole and the steam outlet of the second-effect evaporator are respectively connected with the feed hole and the steam inlet of the third-effect evaporator. The invention carries out evaporation treatment on the NaCl-rich concentrated solution after reverse osmosis treatment by a triple-effect evaporation unit to obtain NaCl crystal salt for recycling. In the triple-effect evaporation unit, the reverse-osmosis concentrated solution sequentially passes through the first effect evaporator, the second effect evaporator and the third effect evaporator, the concentrated solution is heated through steam, the moisture in the concentrated solution is continuously evaporated, NaCl is continuously separated out, and the separation of brine is realized; steam after concentrated solution in the first effect evaporator is evaporated can enter the second effect evaporator to be used as a heating source, and secondary steam in the second effect evaporator can be used as a heating source of the third effect evaporator, so that the energy-saving effect is good.
Preferably, a security filter is arranged between the nanofiltration water production tank and the reverse osmosis device, and a folding filter element with the filtering precision of 4-6 mu m is arranged in the security filter. According to the invention, the security filter is arranged in front of the reverse osmosis device, so that the particles of the wastewater are further removed by the security filter before entering the reverse osmosis device, and the reverse osmosis membrane blockage caused by overhigh concentration of the particles is avoided; and the phenomenon that the particle size of the particles is too large to puncture a reverse osmosis membrane component, salt leakage and the like are caused, and the recovery effect of NaCl is influenced is also avoided.
Preferably, a high-pressure pump is respectively arranged in front of the ultrafiltration device, the nanofiltration device and the reverse osmosis device. The water inlet of the ultrafiltration device, the nanofiltration device and the reverse osmosis device is pressurized by the high-pressure pump to provide enough water inflow and water inflow pressure for each membrane treatment device, so that the water inlet of the membrane treatment device has certain driving force to overcome resistance such as osmotic pressure and the like, the designed water yield is ensured, and the brine separation is effectively realized.
Preferably, the residence time in the first reaction tank in the step (1) is 20-40 min, and CaCl is added2The addition amount of (A) is 8-20 kg/m3Deacidifying the wastewater.
Preferably, in the step (2), the residence time in the second reaction tank is 20-40 min, and 20-40% of Na by mass is added2CO3Solution, Na2CO3The adding amount of the solution is 5-15L/m3Deacidifying the wastewater.
Preferably, the operating pressure of the ultrafiltration device in the step (3) is 2-3 MPa.
Preferably, the mass fraction of the hydrochloric acid added in the step (4) is 10-30%, and the adding amount of the hydrochloric acid is 5-15L/m3Deacidifying the wastewater.
Preferably, the operation pressure of the primary nanofiltration device in the step (5) is 2.5-3.5 MPa, and the operation pressure of the secondary nanofiltration device is 1.5-2.0 MPa.
Preferably, the operating pressure of the reverse osmosis device in the step (6) is 7.5-8 MPa.
Therefore, the beneficial effects of the invention are as follows: through the cooperation of reagent reaction and membrane treatment devices with different levels of precision, SO in the deacidification wastewater can be treated4 2-And Cl-Effective separation is carried out, and finally, Na which has higher purity and can be directly recycled is obtained2SO4And NaCl, so that effective recovery and resource utilization of salts in the deacidification wastewater can be realized, the generation amount of solid waste is reduced, and the energy-saving and emission-reducing degree is improved.
Drawings
Fig. 1 is a schematic view of a connection structure of the present invention.
In the figure: 1 homogenizing tank, 2 first reaction tank, 3 second reaction tank, 4 sedimentation tank, 4-1 sludge hopper, 5 concentration tank, 6 ultrafiltration device, 6-1 ultrafiltration device water inlet, 6-2 ultrafiltration device permeate outlet, 6-3 ultrafiltration device concentrate outlet, 7 ultrafiltration water production tank, 8 defluorination reactor, 9 nanofiltration device, 9-1 primary nanofiltration device, 9-1-1 primary nanofiltration device water inlet, 9-1-2 primary nanofiltration device permeate outlet, 9-1-3 primary nanofiltration device concentrate outlet, 9-2 secondary nanofiltration device, 9-2-1 secondary nanofiltration device water inlet, 9-2-2 secondary nanofiltration device permeate outlet, 9-2-3 secondary nanofiltration device concentrate outlet, 10 nanofiltration water productionA pool, a reverse osmosis device 11-1 water inlet, a reverse osmosis device 11-2 permeate outlet, a reverse osmosis device 11-3 concentrate outlet, a triple effect evaporation unit 12-1 first effect evaporator, a vapor outlet 12-1-1, a feed inlet 12-1-2, a vapor inlet 12-1-3, a condensed water outlet 12-1-4, a discharge outlet 12-1-5, a second effect evaporator 12-2, a third effect evaporator 12-3, a nanofiltration concentrate pool 13, a refrigeration crystallizing device 14, CaCl 152Dosing device, 16Na2CO3A dosing device, a 17 hydrochloric acid dosing device, an 18 sludge pool, an 18-1 sludge inlet, an 18-2 sludge outlet, an 18-3 wastewater outlet, a 19 filter press, a 20 reuse water pool, a 21 security filter and a 22 high-pressure pump.
Detailed Description
The invention is further described with reference to the following detailed description and accompanying drawings.
In the present invention, all the equipment and materials are commercially available or commonly used in the art, and the methods in the following examples are conventional in the art unless otherwise specified.
As shown in fig. 1, a high-salt-content deacidification wastewater resource utilization system comprises a homogenizing tank 1, a first reaction tank 2, a second reaction tank 3, a sedimentation tank 4, a concentration tank 5, an ultrafiltration device 6, an ultrafiltration water-producing tank 7, a defluorination reactor 8, a nanofiltration device 9, a nanofiltration water-producing tank 10, a security filter 21, a reverse osmosis device 11, a three-effect evaporation unit 12, a nanofiltration concentrated solution tank 13 and a freezing crystallization device 14 which are sequentially connected with a wastewater pipeline; CaCl is arranged above the first reaction tank2A chemical adding device 15, Na is arranged above the second reaction tank2CO3A hydrochloric acid dosing device 17 is arranged above the ultrafiltration water producing pool 16.
A sludge pool 18 and a filter press 19 are also arranged in the system; the sludge tank is provided with a sludge inlet 18-1, a sludge outlet 18-2 and a wastewater outlet 18-3; the bottoms of the sedimentation tank 4 and the concentration tank 5 are provided with sludge hoppers 4-1; the sludge inlet of the sludge tank is respectively connected with the sludge buckets of the sedimentation tank and the concentration tank through sludge pipelines, the sludge outlet of the sludge tank is connected with the filter press through sludge pipelines, and the wastewater outlet of the sludge tank is connected with the water inlet of the first reaction tank through a return pipeline.
The ultrafiltration device is provided with an ultrafiltration device water inlet 6-1, an ultrafiltration device permeate outlet 6-2 and an ultrafiltration device concentrated solution outlet 6-3; the water inlet of the ultrafiltration device is connected with the water outlet of the concentration tank, the water inlet of the ultrafiltration device is provided with a high-pressure pump, the permeate outlet of the ultrafiltration device is connected with the ultrafiltration water production tank, and the concentrate outlet of the ultrafiltration device is connected with the water inlet of the concentration tank.
The nanofiltration device comprises a primary nanofiltration device 9-1 and a secondary nanofiltration device 9-2, wherein the primary nanofiltration device and the secondary nanofiltration device are respectively provided with a water inlet, a permeate outlet and a concentrated solution outlet; a water inlet 9-1-1 of the primary nanofiltration device is connected with the defluorination reactor 8 through a wastewater pipeline, a permeate outlet 9-1-2 of the primary nanofiltration device is connected with a water inlet 9-2-1 of the secondary nanofiltration device through a wastewater pipeline, and a concentrate outlet 9-1-3 of the primary nanofiltration device is connected with a nanofiltration concentrate tank 13 through a wastewater pipeline; a permeate outlet 9-2-2 of the secondary nanofiltration device is connected with a nanofiltration water production tank 10 through a waste water pipeline, and a concentrated solution outlet 9-2-3 of the secondary nanofiltration device is connected with a water inlet of the primary nanofiltration device through a return pipeline; the water inlets of the first-stage nanofiltration device and the second-stage nanofiltration device are provided with high-pressure pumps.
The reverse osmosis device is provided with a reverse osmosis device water inlet 11-1, a reverse osmosis device permeate outlet 11-2 and a reverse osmosis device concentrated solution outlet 11-3; a high-pressure pump 22 is arranged at the water inlet of the reverse osmosis device, the water inlet of the reverse osmosis device is connected with the nanofiltration water production tank through a waste water pipeline, and the concentrated solution outlet of the reverse osmosis device is connected with the triple-effect evaporation unit through a waste water pipeline; the system is also provided with a reuse water tank 20 connected with the permeate outlet of the reverse osmosis device.
The ultrafiltration device is provided with a tubular ultrafiltration membrane component, the primary and secondary nanofiltration devices are provided with nanofiltration membrane components, the reverse osmosis device is provided with reverse osmosis membrane components, the defluorination reactor is provided with defluorination resin, and the security filter is provided with a folding filter element with the filtration precision of 5 mu m.
The triple-effect evaporation unit comprises a first effect evaporator 12-1, a second effect evaporator 12-2 and a third effect evaporator 12-3 which are sequentially connected, wherein the top parts of the first effect evaporator, the second effect evaporator and the third effect evaporator are respectively provided with a steam outlet 12-1-1, the middle parts of the first effect evaporator, the second effect evaporator and the third effect evaporator are respectively provided with a feed inlet 12-1-2 and a steam inlet 12-1-3, and the bottom parts of the first effect evaporator, the second effect evaporator and the third effect evaporator are respectively provided with a condensed water outlet 12-1-4 and a discharge outlet 12-1-5; the feed inlet of the first effect evaporator is connected with the concentrated solution outlet of the reverse osmosis device, and the discharge outlet and the steam outlet of the first effect evaporator are respectively connected with the feed inlet and the steam inlet of the second effect evaporator; and the discharge hole and the steam outlet of the second-effect evaporator are respectively connected with the feed hole and the steam inlet of the third-effect evaporator.
Example 1:
a method for resource utilization of high-salt-content deacidification wastewater by using the system comprises the following steps:
(1) the deacidification wastewater enters a first reaction tank after being homogenized by a homogenizing tank, and CaCl is added2Carrying out a reaction of CaCl2The dosage of (A) is 14kg/m3Deacidifying the wastewater, and keeping for 25 min;
(2) the effluent of the first reaction tank enters a second reaction tank, and 30 wt% of Na is added2CO3The solution is reacted with Na2CO3The dosage of the solution is 7.6L/m3Deacidifying the wastewater, and keeping for 25 min;
(3) the effluent of the second reaction tank is sequentially precipitated by a precipitation tank and a concentration tank, the supernatant enters an ultrafiltration system for ultrafiltration, the operating pressure of an ultrafiltration device is 2.4MPa, and the inflow is 30m3/h；
(4) The permeate after ultrafiltration enters an ultrafiltration production water tank, and 30 wt% of hydrochloric acid is added for reaction, wherein the adding amount of the hydrochloric acid is 11.2L/m3Deacidifying the wastewater; refluxing the concentrated solution after ultrafiltration to a concentration tank;
(5) f is removed from the effluent of the ultrafiltration water production tank through a defluorination reactor-Then sequentially passing through a first-stage nanofiltration device and a second-stage nanofiltration device to carry out two-stage nanofiltration; the operating pressure of the first-stage nanofiltration device is 3.0MPa, and the water inlet flow is 1.2m3H, the operating pressure of the secondary nanofiltration device is 1.8MPa, and the water inlet flow is 1.2m3H; the concentrated solution after two-stage nanofiltration enters a freezing crystallization device, and Na is recovered after freezing crystallization2SO4；
(6) The permeate liquid after two-stage nanofiltration enters a nanofiltration water producing tank, then enters a reverse osmosis device after passing through a security filterReverse osmosis is carried out, the operating pressure of a reverse osmosis device is 7.8MPa, and the water inlet flow is 0.15m3/h；
(7) And (4) the permeate after reverse osmosis enters a reuse water pool, and the concentrated solution enters a triple-effect evaporation unit, and NaCl is obtained after evaporation and recovery.
Wherein, the tubular ultrafiltration membrane in the ultrafiltration device adopts PEROX with the treatment capacity of 1m3H, 1 inch of 10-core tubular ultrafiltration membrane; the nanofiltration membranes in the primary nanofiltration device and the secondary nanofiltration device adopt DOW NF 8040; the reverse osmosis membrane in the reverse osmosis device adopts DOW SW 30-400; the defluorinating resin in the defluorinating reactor is Dusheng CH-87.
Example 2:
in example 2, the method for preparing the nanofiltration membrane in the primary and secondary nanofiltration devices comprises the following steps:
A) ZrCl with the molar ratio of 1:1.54And 2-amino terephthalic acid in DMF, ZrCl4The mass-to-volume ratio of DMF to DMF is 1g:120 mL; adding hydrochloric acid, performing ultrasonic dispersion for 25min, heating to 130 ℃, performing hydrothermal reaction for 30h, cooling to room temperature, filtering, cleaning and drying a product to obtain a metal organic framework material; wherein the mass concentration of the added hydrochloric acid is 36 percent, and the volume ratio of the added hydrochloric acid to DMF is 1: 55;
B) adding a metal organic framework material and N-methylimidazole into ethanol, and stirring for 14 hours under the protection of nitrogen; then 3-bromopropylamine hydrobromide is added for reflux reaction for 30 hours under the protection of nitrogen; wherein the mass ratio of the metal organic framework material to the N-methylimidazole to the 3-bromopropylamine hydrobromide is 2.3:1: 2.93; filtering the product, washing the product with ethanol, and drying the product in vacuum at 80 ℃ to obtain the ionic liquid modified metal organic framework material;
C) dissolving piperazine in deionized water, adding an ionic liquid modified metal organic framework material, uniformly dispersing, and adjusting the pH value of the solution to 6 to obtain an aqueous phase solution, wherein the mass concentration of piperazine in the aqueous phase solution is 0.3%, and the mass ratio of piperazine to the metal organic framework material is 3: 1;
D) adding trimesoyl chloride into ethylcyclohexane, stirring and dissolving to obtain an oil phase solution with the mass concentration of the trimesoyl chloride of 0.15%;
E) soaking the porous polysulfone base membrane in the water phase solution for 7min, taking out, and blowing the residual water phase solution on the base membrane until no water drop exists on the surface of the base membrane; then immersing the basement membrane into the oil phase solution for contact reaction for 3 min; taking out the membrane, predrying the base membrane for 1.5min at 60 ℃, then washing the membrane for 5min by using hot water at 80 ℃, then soaking the membrane for 2min in glycerol with the mass concentration of 8%, taking out the membrane and drying the membrane at 60 ℃ to obtain the nanofiltration membrane.
The rest is the same as in example 1.
Example 3:
a method for resource utilization of high-salt-content deacidification wastewater by using the system comprises the following steps:
(1) the deacidification wastewater enters a first reaction tank after being homogenized by a homogenizing tank, and CaCl is added2Carrying out a reaction of CaCl2The addition amount of (A) is 8kg/m3Deacidifying the wastewater, and keeping for 20 min;
(2) the effluent of the first reaction tank enters a second reaction tank, and 40 wt% of Na is added2CO3The solution is reacted with Na2CO3The dosage of the solution is 5L/m3Deacidifying the wastewater, and keeping for 20 min;
(3) the effluent of the second reaction tank is sequentially precipitated by a precipitation tank and a concentration tank, the supernatant enters an ultrafiltration system for ultrafiltration, the operating pressure of an ultrafiltration device is 2.0MPa, and the inflow is 30m3/h；
(4) The permeate after ultrafiltration enters an ultrafiltration production water tank, and 30 wt% of hydrochloric acid is added for reaction, wherein the adding amount of the hydrochloric acid is 5L/m3Deacidifying the wastewater; refluxing the concentrated solution after ultrafiltration to a concentration tank;
(5) f is removed from the effluent of the ultrafiltration water production tank through a defluorination reactor-Then sequentially passing through a first-stage nanofiltration device and a second-stage nanofiltration device to carry out two-stage nanofiltration; the operation pressure of the first-stage nanofiltration device is 2.5MPa, and the inflow is 1.2m3H, the operating pressure of the secondary nanofiltration device is 1.5MPa, and the water inflow is 1.2m3H; the concentrated solution after two-stage nanofiltration enters a freezing crystallization device, and Na is recovered after freezing crystallization2SO4；
(6) The permeate liquid after two-stage nanofiltration enters a nanofiltration water producing tank, then enters a reverse osmosis water producing tank after passing through a security filterReverse osmosis is carried out in the device, the operating pressure of the reverse osmosis device is 7.5MPa, and the water inlet flow is 0.15m3/h；
(7) And (4) the permeate after reverse osmosis enters a reuse water pool, and the concentrated solution enters a triple-effect evaporation unit, and NaCl is obtained after evaporation and recovery.
The preparation method of the nanofiltration membrane in the primary nanofiltration device and the secondary nanofiltration device comprises the following steps:
A) ZrCl with the molar ratio of 1:14And 2-amino terephthalic acid in DMF, ZrCl4The mass-to-volume ratio of DMF to DMF is 1g:100 mL; adding hydrochloric acid, performing ultrasonic dispersion for 20min, heating to 120 ℃ for hydrothermal reaction for 36h, cooling to room temperature, filtering, cleaning and drying a product to obtain a metal organic framework material; wherein the mass concentration of the added hydrochloric acid is 35 percent, and the volume ratio of the added hydrochloric acid to DMF is 1: 60;
B) adding a metal organic framework material and N-methylimidazole into ethanol, and stirring for 12 hours under the protection of nitrogen; then 3-bromopropylamine hydrobromide is added for reflux reaction for 36 hours under the protection of nitrogen; wherein the mass ratio of the metal organic framework material to the N-methylimidazole to the 3-bromopropylamine hydrobromide is 2:1: 2.9; filtering the product, washing the product with ethanol, and drying the product in vacuum at 80 ℃ to obtain the ionic liquid modified metal organic framework material;
C) dissolving piperazine in deionized water, adding an ionic liquid modified metal organic framework material, uniformly dispersing, and adjusting the pH value of the solution to 5 to obtain an aqueous phase solution, wherein the mass concentration of piperazine in the aqueous phase solution is 0.2%, and the mass ratio of piperazine to the metal organic framework material is 2: 1;
D) adding trimesoyl chloride into ethylcyclohexane, stirring and dissolving to obtain an oil phase solution with the mass concentration of the trimesoyl chloride of 0.1%;
E) soaking the porous polysulfone base membrane in the water phase solution for 5min, taking out, and blowing the residual water phase solution on the base membrane until no water drop exists on the surface of the base membrane; then immersing the base membrane into the oil phase solution for contact reaction for 2 min; taking out the membrane, pre-drying the base membrane at 50 ℃ for 2min, then washing the membrane with hot water at 70 ℃ for 6min, soaking the membrane in glycerol with the mass concentration of 7% for 3min, taking out the membrane, and drying the membrane at 50 ℃ to obtain the nanofiltration membrane.
Example 4:
a method for resource utilization of high-salt-content deacidification wastewater by using the system comprises the following steps:
(1) the deacidification wastewater enters a first reaction tank after being homogenized by a homogenizing tank, and CaCl is added2Carrying out a reaction of CaCl2The dosage of (A) is 20kg/m3Deacidifying the wastewater, and keeping the wastewater for 40 min;
(2) the effluent of the first reaction tank enters a second reaction tank, and 20 wt% of Na is added2CO3The solution is reacted with Na2CO3The dosage of the solution is 15L/m3Deacidifying the wastewater, and keeping the wastewater for 40 min;
(3) the effluent of the second reaction tank is sequentially precipitated by a precipitation tank and a concentration tank, the supernatant enters an ultrafiltration system for ultrafiltration, the operating pressure of an ultrafiltration device is 3.0MPa, and the inflow is 30m3/h；
(4) The permeate after ultrafiltration enters an ultrafiltration water production tank, 10 wt% of hydrochloric acid is added for reaction, and the adding amount of the hydrochloric acid is 15.0L/m3Deacidifying the wastewater; refluxing the concentrated solution after ultrafiltration to a concentration tank;
(5) f is removed from the effluent of the ultrafiltration water production tank through a defluorination reactor-Then sequentially passing through a first-stage nanofiltration device and a second-stage nanofiltration device to carry out two-stage nanofiltration; the operation pressure of the first-stage nanofiltration device is 3.5MPa, and the inflow is 1.2m3H, the operating pressure of the secondary nanofiltration device is 2.0MPa, and the water inlet flow is 1.2m3H; the concentrated solution after two-stage nanofiltration enters a freezing crystallization device, and Na is recovered after freezing crystallization2SO4；
(6) The permeate liquid after two-stage nanofiltration enters a nanofiltration water production tank, then enters a reverse osmosis device for reverse osmosis after passing through a security filter, the operating pressure of the reverse osmosis device is 8.0MPa, and the water inlet flow is 0.15m3/h；
(7) And (4) the permeate after reverse osmosis enters a reuse water pool, and the concentrated solution enters a triple-effect evaporation unit, and NaCl is obtained after evaporation and recovery.
The preparation method of the nanofiltration membrane in the primary nanofiltration device and the secondary nanofiltration device comprises the following steps:
A) ZrCl with the molar ratio of 1:24And 2-amino terephthalic acid in DMF, ZrCl4The mass-to-volume ratio of DMF to DMF is 1g:150 mL; adding hydrochloric acid, performing ultrasonic dispersion for 30min, heating to 140 ℃, performing hydrothermal reaction for 24h, cooling to room temperature, filtering, cleaning and drying a product to obtain a metal organic framework material; wherein the mass concentration of the added hydrochloric acid is 37 percent, and the volume ratio of the added hydrochloric acid to DMF is 1: 50;
B) adding a metal organic framework material and N-methylimidazole into ethanol, and stirring for 18 hours under the protection of nitrogen; then 3-bromopropylamine hydrobromide is added for reflux reaction for 24 hours under the protection of nitrogen; wherein the mass ratio of the metal organic framework material to the N-methylimidazole to the 3-bromopropylamine hydrobromide is 2.5:1: 2.95; filtering the product, washing the product with ethanol, and drying the product in vacuum at 80 ℃ to obtain the ionic liquid modified metal organic framework material;
C) dissolving piperazine in deionized water, adding an ionic liquid modified metal organic framework material, uniformly dispersing, and adjusting the pH value of the solution to 7 to obtain an aqueous phase solution, wherein the mass concentration of piperazine in the aqueous phase solution is 0.4%, and the mass ratio of piperazine to the metal organic framework material is 4: 1;
D) adding trimesoyl chloride into ethylcyclohexane, stirring and dissolving to obtain an oil phase solution with the mass concentration of the trimesoyl chloride of 0.2%;
E) immersing the porous polysulfone base membrane into the water phase solution for soaking for 10min, taking out the porous polysulfone base membrane, and blowing the residual water phase solution on the base membrane to be clean until no water drops exist on the surface of the base membrane; then immersing the basement membrane into the oil phase solution for contact reaction for 5 min; taking out the membrane, pre-drying the base membrane at 70 ℃ for 1min, then washing the membrane with hot water at 90 ℃ for 4min, soaking the membrane in glycerol with the mass concentration of 9% for 1min, taking out the membrane, and drying the membrane at 70 ℃ to obtain the nanofiltration membrane.
Comparative example 1 (CaCl)2Too low dosage):
CaCl in step (1) of comparative example 12The addition amount of (A) is 7kg/m3The deacidification of the wastewater was carried out as in example 1.
Comparative example 2 (ionic liquid directly blended with metal organic framework):
the preparation method of the nanofiltration membranes in the first-stage nanofiltration device and the second-stage nanofiltration device in the comparative example 2 comprises the following steps:
A) ZrCl with the molar ratio of 1:1.54And 2-amino terephthalic acid in DMF, ZrCl4The mass-to-volume ratio of DMF to DMF is 1g:120 mL; adding hydrochloric acid, performing ultrasonic dispersion for 25min, heating to 130 ℃, performing hydrothermal reaction for 30h, cooling to room temperature, filtering, cleaning and drying a product to obtain a metal organic framework material; wherein the mass concentration of the added hydrochloric acid is 36 percent, and the volume ratio of the added hydrochloric acid to DMF is 1: 55;
B) dissolving piperazine in deionized water, adding a metal organic framework material and ionic liquid 1- (3-aminopropyl) -3-methylimidazole bromine, uniformly dispersing, and adjusting the pH value of the solution to 6 to obtain an aqueous phase solution, wherein the mass concentration of piperazine in the aqueous phase solution is 0.3%, and the mass ratio of piperazine to the metal organic framework material to 1- (3-aminopropyl) -3-methylimidazole bromine is 3:1: 1.7;
C) adding trimesoyl chloride into ethylcyclohexane, stirring and dissolving to obtain an oil phase solution with the mass concentration of the trimesoyl chloride of 0.15%;
D) soaking the porous polysulfone base membrane in the water phase solution for 7min, taking out, and blowing the residual water phase solution on the base membrane until no water drop exists on the surface of the base membrane; then immersing the basement membrane into the oil phase solution for contact reaction for 3 min; taking out the membrane, predrying the base membrane for 1.5min at 60 ℃, then washing the membrane for 5min by using hot water at 80 ℃, then soaking the membrane for 2min in glycerol with the mass concentration of 8%, taking out the membrane and drying the membrane at 60 ℃ to obtain the nanofiltration membrane.
The rest is the same as in example 2.
Firstly, determination of deacidification wastewater treatment effect:
the water quality during the treatment of example 1 and comparative example 1 was tested and the results are shown in tables 1 and 2.
Table 1: example 1 results of water quality condition test at each stage.
Figure BDA0003166658870000121
Table 2: example 1 and comparative example 1 the first reaction tank effluent quality condition test results.
Figure BDA0003166658870000122
As can be seen from tables 1 and 2, in example 1, the process of the present invention was used to effectively reduce F in deacidification wastewater-、CO3 2-、HCO3 -Content of (a) to (b) F-、CO3 2-、HCO3 -Removing; the second-stage nanofiltration concentrated solution has higher SO4 2-Content of Na can be realized2SO4Recovering; the reverse osmosis effluent has low TDS concentration and can be directly recycled; the reverse osmosis concentrated solution has higher Cl-And the concentration can realize the recovery of NaCl.
And CaCl in the first reaction tank in comparative example 12Too small an amount of F-、CO3 2-、HCO3 -And SO4 2-The removal effect of (a) is significantly reduced compared to that in example 1.
Secondly, measuring the nano-filtration salt separation effect:
the nanofiltration membranes used in the above examples and comparative examples were subjected to a cross-flow filtration test using a 1000ppm mixed solution of magnesium sulfate and sodium chloride under a test pressure of 0.7MPa and a test temperature of 25 deg.C, and their water flux and SO were measured4 2-With Cl-The results are shown in table 3.
Table 3: and (5) testing the performance of the nanofiltration membrane.
Test items Example 1 Example 2 Example 3 Example 4 Comparative example 3
Water flux (L/m)2h) 62 88 91 82 110
SO4 2-Retention (%) 99.02 99.33 98.89 99.61 95.48
Cl-Retention (%) 4.2 6.8 5.9 7.4 4.7
As can be seen from Table 1, the nanofiltration membranes prepared by the method of the invention in examples 2-4 have significantly improved water flux and Cl content compared with the commercial nanofiltration membrane in example 1-While passing through the SO4 2-Has high retention rate. In the nanofiltration membrane preparation process in the comparative example 3, the ionic liquid and the metal organic framework are directly blended and added into the aqueous phase solution, and the ionic liquid is not loaded on the metal organic framework materialIn addition, the water flux of the prepared nanofiltration membrane is obviously improved compared with that of the nanofiltration membrane in example 2, but the water flux is obviously improved for SO4 2-The rejection rate is reduced, which is not beneficial to the recovery of NaCl; probably because the density of the formed polypiperazine amide functional layer can be reduced under the influence of steric hindrance and the like of the ionic liquid after the ionic liquid is directly added into the aqueous phase solution, SO that the nanofiltration membrane can reduce SO caused by the nanofiltration membrane4 2-The retention rate is reduced, and the influence of the ionic liquid on the density of the polypiperazine amide functional layer can be reduced after the ionic liquid is loaded in the metal organic framework material.
Water yield (water yield/water inflow x 100%) of the nanofiltration device during operation of the systems of examples and comparative examples, and for SO4 2-The retention of (c) was tested and the results are shown in table 4.
Table 4: nanofiltration device water production flow and SO4 2-And (5) testing the retention rate.
Figure BDA0003166658870000131
As can be seen from Table 4, when the nanofiltration membrane prepared in the present invention was used in example 2, the water yield and SO yield of the nanofiltration apparatus were higher than those of the commercial nanofiltration membrane used in example 14 2-The retention rate is improved; in the comparative example 2, the nanofiltration membrane prepared by directly blending the ionic liquid and the metal organic framework into the aqueous phase solution is used, SO although the water yield is improved to some extent4 2-The rejection rate is obviously reduced, and NaCl and Na are not beneficial2SO4And (4) recovering.
Thirdly, recycling the water quality and NaCl and Na2SO4And (3) testing the recovery effect:
the quality of the reuse water obtained after reverse osmosis and Na obtained by freeze crystallization in the above examples and comparative examples2SO4Purity, NaCl purity by triple effect evaporation was tested and the results are shown in table 5.
Table 5: and (5) recovering the effect test result.
Figure BDA0003166658870000132
Figure BDA0003166658870000141
As can be seen from table 5, the recycle water obtained using the system and method of the present invention has low TDS and can be directly recycled or discharged; recovering the obtained NaCl and Na2SO4The purity is high, the physical and chemical index requirements of industrial salt and anhydrous sodium sulfate standards can be met, and resource utilization can be carried out.

Claims (10)

1. A resource utilization system for deacidification wastewater with high salt content is characterized by comprising a homogenizing tank (1), a first reaction tank (2), a second reaction tank (3), a sedimentation tank (4), a concentration tank (5), an ultrafiltration device (6), an ultrafiltration water-producing tank (7), a nanofiltration device (9), a nanofiltration water-producing tank (10), a reverse osmosis device (11), a triple-effect evaporation unit (12) and a nanofiltration concentrated solution tank (13) and a freezing crystallization device (14) which are sequentially connected with each other; CaCl is arranged above the first reaction tank2A chemical adding device (15), Na is arranged above the second reaction tank2CO3A hydrochloric acid dosing device (17) is arranged above the ultrafiltration water producing tank.
2. The resource utilization system for deacidification wastewater with high salt content according to claim 1, wherein a sludge tank (18) and a filter press (19) which are connected are further arranged in the system; a sludge inlet (18-1), a sludge outlet (18-2) and a wastewater outlet (18-3) are arranged on the sludge tank; the bottoms of the sedimentation tank and the concentration tank are provided with sludge hoppers (4-1); the sludge inlet of the sludge tank is respectively connected with the sludge buckets of the sedimentation tank and the concentration tank, the sludge outlet of the sludge tank is connected with the filter press, and the wastewater outlet of the sludge tank is connected with the water inlet of the first reaction tank.
3. The resource utilization system for deacidification wastewater with high salt content according to claim 1, wherein a tubular ultrafiltration membrane component is arranged in the ultrafiltration device; the ultrafiltration device is provided with an ultrafiltration device water inlet (6-1), an ultrafiltration device permeate outlet (6-2) and an ultrafiltration device concentrate outlet (6-3), the ultrafiltration device water inlet is connected with a water outlet of the concentration tank, the ultrafiltration device permeate outlet is connected with the ultrafiltration water production tank, and the ultrafiltration device concentrate outlet is connected with a water inlet of the concentration tank.
4. The resource utilization system of deacidified wastewater with high salt content as claimed in claim 1, wherein the nanofiltration device comprises a primary nanofiltration device (9-1) and a secondary nanofiltration device (9-2), nanofiltration membrane components are arranged in the primary and secondary nanofiltration devices, and a water inlet, a permeate outlet and a concentrated solution outlet are respectively arranged on the primary and secondary nanofiltration devices; a water inlet (9-1-1) of the primary nanofiltration device is connected with the defluorination reactor (8), a permeate outlet (9-1-2) of the primary nanofiltration device is connected with a water inlet (9-2-1) of the secondary nanofiltration device, and a concentrate outlet (9-1-3) of the primary nanofiltration device is connected with a nanofiltration concentrate pool (13); a permeate outlet (9-2-2) of the secondary nanofiltration device is connected with a nanofiltration water production tank (10), and a concentrate outlet (9-2-3) of the secondary nanofiltration device is connected with a water inlet of the primary nanofiltration device.
5. The resource utilization system for deacidification wastewater with high salt content according to claim 1, wherein a reverse osmosis membrane module is arranged in the reverse osmosis device, and the reverse osmosis device is provided with a reverse osmosis device water inlet (11-1), a reverse osmosis device permeate outlet (11-2) and a reverse osmosis device concentrate outlet (11-3); the water inlet of the reverse osmosis device is connected with the nanofiltration water production tank, and the concentrated solution outlet of the reverse osmosis device is connected with the triple-effect evaporation unit; the system is also internally provided with a reuse water pool (20) connected with a permeate outlet of the reverse osmosis device.
6. The resource utilization system for deacidification wastewater with high salt content according to claim 5, characterized in that the triple-effect evaporation unit comprises a first effect evaporator (12-1), a second effect evaporator (12-2) and a third effect evaporator (12-3) which are connected in sequence, the top parts of the first, second and third effect evaporators are respectively provided with a steam outlet (12-1-1), the middle parts of the first, second and third effect evaporators are respectively provided with a feed inlet (12-1-2) and a steam inlet (12-1-3), and the bottom parts of the first, second and third effect evaporators are respectively provided with a condensed water outlet (12-1-4) and a discharge outlet (12-1-5); the feed inlet of the first effect evaporator is connected with a concentrated solution outlet of the reverse osmosis device, and the discharge outlet and a steam outlet of the first effect evaporator are respectively connected with the feed inlet and a steam inlet of the second effect evaporator; and the discharge hole and the steam outlet of the second-effect evaporator are respectively connected with the feed hole and the steam inlet of the third-effect evaporator.
7. A method for recycling high-salt-content deacidification wastewater by using the system as claimed in any one of claims 1 to 6, which is characterized by comprising the following steps:
(1) the deacidification wastewater enters a first reaction tank after being homogenized by a homogenizing tank, and CaCl is added2Carrying out reaction;
(2) the effluent of the first reaction tank enters a second reaction tank, and Na is added2CO3Carrying out reaction;
(3) after the effluent of the second reaction tank sequentially passes through a sedimentation tank and a concentration tank for sedimentation, the supernatant enters an ultrafiltration system for ultrafiltration;
(4) the permeate after ultrafiltration enters an ultrafiltration water producing tank, and hydrochloric acid is added for reaction;
(5) the effluent of the ultrafiltration water production tank enters a nanofiltration device for nanofiltration, the nanofiltration concentrated solution enters a freezing crystallization device, and Na is obtained by recycling after freezing crystallization2SO4；
(6) The permeate after nanofiltration enters a reverse osmosis device for reverse osmosis through a nanofiltration water production pool;
(7) and (4) the concentrated solution after reverse osmosis enters a triple-effect evaporation unit, and NaCl is obtained after evaporation and recovery.
8. The resource utilization method of high-salt-content deacidification wastewater according to claim 7The method is characterized in that in the step (1), the retention time in the first reaction tank is 20-40 min, and CaCl is added2The addition amount of (A) is 8-20 kg/m3Deacidifying the wastewater.
9. The method for resource utilization of deacidification wastewater with high salt content according to claim 7, characterized in that in step (2), the residence time in the second reaction tank is 20-40 min, and Na with the mass fraction of 20-40% is added2CO3Solution, Na2CO3The adding amount of the solution is 5-15L/m3Deacidifying the wastewater.
10. The method for resource utilization of deacidification wastewater with high salt content according to claim 7, wherein the mass fraction of hydrochloric acid added in step (4) is 10-30%, and the adding amount of hydrochloric acid is 5-15L/m3Deacidifying the wastewater.
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