Hardness removal device and method for high-hardness salt-containing wastewater

Abstract

The invention relates to a hardness removal device and method for high-hardness salt-containing wastewater, the device comprises an exchange unit, a regeneration unit and a regenerated waste liquid disposal unit, wastewater flows through ion exchange resin from bottom to top in an exchange column and is in countercurrent contact with the ion exchange resin, so that the effect of removing hardness in the wastewater is achieved; the saturated resin sequentially passes through the first regeneration column, the second regeneration column and the third regeneration column to be subjected to first-stage regeneration, second-stage regeneration and third-stage regeneration, first-stage regeneration liquid sequentially enters the third regeneration column, the second regeneration column and the first regeneration column to regenerate the resin, and a countercurrent regeneration mode is adopted to improve the regeneration degree of the resin; the regenerated resin is transferred to an exchange column for ion exchange, and regenerated waste liquid is transferred to a regenerated waste liquid treatment unit for treatment. The method can replace a traditional chemical softening method and a cation bed softening method for combined hardness removal, realizes thorough removal of high hardness, reduces the dosage of a hardness removal agent, and solves the problem of deposition and blockage of calcium sulfate scale formed by sodium sulfate as a regeneration solution.

Description

Technical Field

[0001] The present invention belongs to the technical field of saline wastewater treatment, and in particular relates to a hardness removal device and method for high-hardness saline wastewater. Background Art

[0002] The conventional treatment process for high-hardness salt-containing wastewater is a chemical softening process as a pretreatment. The hardness is reduced to 100 mg / L to 150 mg / L by adding a large amount of hardness removal agents. After the first-level membrane concentration, the concentrated water is further chemically softened and then further removed through a cationic bed softening process to meet the requirements of the membrane concentration system and the evaporation crystallization system for the inlet water hardness.

[0003] Although conventional treatment processes are relatively mature, there are still many problems in actual operation. For example, it is difficult to control the amount of hardness removal agent added in real time according to the hardness of the incoming water during the actual dosing process. Therefore, in order to ensure the hardness removal effect, the dosage is usually controlled according to a higher hardness value, resulting in excessive addition of hardness removal agent, which greatly increases the cost of the agent. At the same time, excessive addition of agents will also lead to an increase in the salt content of the wastewater, increasing the investment and operating costs of membrane concentration and evaporation crystallization.

[0004] If the conventional cationic bed resin softening process is used to treat high-hardness wastewater, the regeneration cycle will be greatly shortened, regeneration will be frequent, or the resin filling amount will be greatly increased, the investment will be high, and a large amount of acid, alkali or salt regeneration agents will be required. Therefore, conventional cationic bed resin is not suitable for treating high-hardness saline wastewater, but only for treating low-hardness wastewater as a subsequent deep treatment process of chemical softening. In addition, the conventional cationic bed resin softening process will increase the salt content of the system due to the addition of acid, alkali or salt regeneration agents, which will also increase the investment and operating costs of membrane concentration and evaporation crystallization.

[0005] When the resin is regenerated with salt, sodium chloride is generally used for regeneration, and the regeneration waste liquid is discharged to the front-end regulating tank or sedimentation tank. If sodium sulfate is used for regeneration, calcium sulfate crystals will precipitate and deposit on the resin bed and the wall of the equipment, gradually forming calcium sulfate scale with higher hardness. Summary of the invention

[0006] In view of the defects existing in the prior art, the purpose of the present invention is to provide a hardness removal device and method for high-hardness salt-containing wastewater, which adopts sodium sulfate solution, sodium sulfate and sodium chloride mixed solution, and membrane concentration system concentrated water as regeneration liquid, which can replace the traditional chemical softening method and cationic bed softening method for combined hardness removal, and achieve the complete removal of high hardness. The regenerated waste liquid can form calcium sulfate precipitation without adding drugs, which greatly reduces the dosage of hardness removal agent. Compared with the conventional hardness removal process, the salt content of the system is greatly reduced; at the same time, it solves the problem of calcium sulfate scale deposition and blockage caused by sodium sulfate as the regeneration liquid.

[0007] In order to achieve the above purpose, the technical solution adopted by the present invention is: a hardness removal device for high-hardness saline wastewater, the device includes an exchange unit, a regeneration unit, and a regeneration waste liquid disposal unit, wherein:

[0008] The exchange unit comprises an exchange column, a water inlet tank, a water production tank, and a water inlet pump. The water inlet tank is connected to the water inlet at the bottom of the exchange column through the water inlet pump, and the water outlet at the top of the exchange column is connected to the water production tank through the exchange column outlet pipe; an exchange column resin storage is installed on the top of the exchange column;

[0009] The regeneration unit comprises a first regeneration column, a second regeneration column, a third regeneration column, a water washing column, a first regeneration liquid tank, a second regeneration liquid tank, a third regeneration liquid tank, a regeneration waste liquid storage tank, a compressed air storage tank, a first regeneration liquid pump, a second regeneration liquid pump, a third regeneration liquid pump, and a water washing column water inlet pump;

[0010] The top of the first regeneration column is connected to the first resin grid and the first resin storage tank through pipelines from top to bottom, and the bottom outlet of the exchange column is connected to the first resin grid through the first resin transfer pipe; the bottom water inlet of the first regeneration column is connected to the first regeneration liquid tank through the first regeneration liquid pump, and the top water outlet of the first regeneration column is connected to the water inlet of the regeneration waste liquid storage tank;

[0011] The top of the second regeneration column is connected to the second resin grid and the second resin storage device through pipelines from top to bottom, and the bottom outlet of the first regeneration column is connected to the second resin grid through a second resin transfer pipe; the bottom water inlet of the second regeneration column is connected to the second regeneration liquid tank through a second regeneration liquid pump, and the top water outlet of the second regeneration column is connected to the water inlet of the first regeneration liquid tank;

[0012] The third regeneration column is connected to the third resin storage via a pipeline, and the bottom outlet of the second regeneration column is connected to the third resin storage via a third resin transfer pipe; the bottom water inlet of the third regeneration column is connected to the third regeneration liquid tank via a third regeneration liquid pump, and the top water outlet of the third regeneration column is connected to the water inlet of the second regeneration liquid tank;

[0013] The water washing column is connected to the fourth resin storage via a pipeline, and the bottom outlet of the third regeneration column is connected to the fourth resin storage at the top of the water washing column via a fourth resin transfer pipe; the water inlet at the bottom of the water washing column is connected to the water production tank via a water washing column water inlet pump, and the water outlet at the top of the water washing column is connected to the water inlet tank; the bottom outlet of the water washing column is connected to the exchange column resin storage via a fifth resin transfer pipe;

[0014] The first resin transfer pipe, the second resin transfer pipe, the third resin transfer pipe, and the fourth resin transfer pipe are respectively connected to the air outlet of the compressed air storage tank;

[0015] The regeneration waste liquid disposal unit includes a primary sedimentation tank for regeneration waste liquid, a secondary sedimentation tank for regeneration waste liquid, a sludge pump, and a dosing system; the outlet of the regeneration waste liquid storage tank is connected to the water inlet of the primary sedimentation tank for regeneration waste liquid through a sludge pump, and the water outlet of the primary sedimentation tank for regeneration waste liquid is connected to the water inlet of the secondary sedimentation tank for regeneration waste liquid; the dosing system is connected to the coagulation zone and flocculation zone of the secondary sedimentation tank for regeneration waste liquid; the outlet of the secondary sedimentation tank for regeneration waste liquid is connected to the subsequent membrane concentration or evaporation crystallization unit through a regeneration liquid reflux pipe.

[0016] Furthermore, the first resin grid water inlet is connected to the water production tank through a grid flushing water pump; the first resin grid water outlet is connected to the flushing wastewater inlet of the water inlet tank through a first grid flushing wastewater pipe;

[0017] The water inlet of the second resin grid is connected to the water production tank through a grid flushing water pump; the water outlet of the second resin grid is connected to the flushing wastewater inlet of the regeneration waste liquid storage tank through a second grid flushing wastewater pipe.

[0018] Furthermore, the regeneration unit also includes a first regeneration liquid tank agitator installed in the first regeneration liquid tank; the regeneration unit also includes a second regeneration liquid tank agitator installed in the third regeneration liquid tank; the regeneration unit also includes a third regeneration liquid tank agitator installed in the regeneration waste liquid storage tank.

[0019] Further, an exchange column resin storage valve is installed between the exchange column resin storage and the top of the exchange column;

[0020] A first resin storage valve is installed between the first regeneration column and the first resin storage;

[0021] A second resin storage valve is installed between the second regeneration column and the second resin storage;

[0022] A third resin storage valve is installed between the third regeneration column and the third resin storage;

[0023] A fourth resin storage valve is installed between the water washing column and the fourth resin storage.

[0024] Furthermore, the air inlet at the bottom of the first regeneration column is connected to the air outlet of the compressed air storage tank through a stirring air pipe.

[0025] Further, the first resin transfer pipe, the second resin transfer pipe, the third resin transfer pipe, and the fourth resin transfer pipe are respectively connected to the air outlet of the compressed air storage tank through the resin transfer air pipe;

[0026] The resin transfer air pipe is provided with a resin transfer pneumatic valve.

[0027] The present invention also provides a method for removing hardness from high-hardness saline wastewater, which is implemented based on the device for removing hardness from high-hardness saline wastewater. The method comprises the following steps:

[0028] S1. Ion exchange: The ion exchange resin enters the exchange column from the exchange column resin storage, and the wastewater in the water inlet tank is transported into the exchange column from the water inlet at the bottom of the exchange column by the water inlet pump; when the wastewater flows through the exchange column from bottom to top, it exchanges ions with the sodium ions on the ion exchange resin, and the hardness of the wastewater is removed to obtain the produced water, which enters the water production tank from the water outlet at the top of the exchange column through the exchange column outlet pipe; the saturated resin formed by the ion exchange resin enters the regeneration unit for further regeneration;

[0029] S2. Resin regeneration: In the regeneration unit, the saturated resin passes through the first regeneration column, the second regeneration column, and the third regeneration column in sequence for primary regeneration, secondary regeneration, and tertiary regeneration. The primary regeneration liquid enters the third regeneration column, the second regeneration column, and the first regeneration column in sequence to regenerate the resin. A countercurrent regeneration method is used to improve the resin regeneration degree. The obtained regenerated resin is transferred to the exchange column resin storage for ion exchange, and the generated regeneration waste liquid is transferred to the regeneration waste liquid disposal unit for treatment;

[0030] S3. Regeneration waste liquid disposal: The regeneration waste liquid in the regeneration waste liquid storage tank is processed in turn through the regeneration waste liquid primary sedimentation tank and the regeneration waste liquid secondary sedimentation tank.

[0031] Furthermore, in step S2, the saturated resin is sequentially subjected to primary regeneration, secondary regeneration, and tertiary regeneration by passing through a first regeneration column, a second regeneration column, and a third regeneration column, and then further subjected to a water washing step to obtain the regenerated resin.

[0032] Furthermore, the exchange column adopts an intermittent moving bed or a continuous moving bed;

[0033] The rising velocity of wastewater in the exchange column is 5 to 15 m / h; the residence time of the resin in the exchange column is 2 to 8 hours.

[0034] Further, in the regeneration unit, the resin residence time is 8 to 16 hours;

[0035] The first regeneration column uses a fluidized bed, and the residence time of the tertiary regeneration liquid in the first regeneration column is 2 to 10 hours;

[0036] The second regeneration column uses a fluidized bed, and the rising velocity of the secondary regeneration liquid is 15-30m / h;

[0037] The third regeneration column adopts an intermittent moving bed or a continuous moving bed, and the rising flow rate of the first-stage regeneration liquid is 5 to 10 m / h.

[0038] Furthermore, the primary regeneration liquid is a sodium sulfate solution, or a mixture of sodium sulfate and sodium chloride, or concentrated water from a membrane concentration system;

[0039] In the primary regeneration liquid, the sodium ion content is greater than 15000 mg / L, and the sulfate ion content is greater than 15000 mg / L.

[0040] The beneficial effect of the present invention lies in that a hardness removal device and method for high-hardness salt-containing wastewater provided by the present invention is adopted, and the device includes an exchange unit, a regeneration unit, and a regeneration waste liquid disposal unit. The wastewater flows through the ion exchange resin from bottom to top in the exchange column, and the ion exchange resin moves from top to bottom. The wastewater is in countercurrent contact with the ion exchange resin, and the calcium and magnesium ions in the wastewater are exchanged with the sodium ions on the ion exchange resin to achieve the effect of removing the hardness in the wastewater; the saturated resin passes through the first regeneration column, the second regeneration column, and the third regeneration column in turn for primary regeneration, secondary regeneration, and tertiary regeneration, and the primary regeneration liquid enters the third regeneration column, the second regeneration column, and the first regeneration column in turn to regenerate the resin, and a countercurrent regeneration method is adopted to improve the regeneration degree of the resin; the obtained regenerated resin is transferred to the exchange column for ion exchange, and the formed regeneration waste liquid is transferred to the regeneration waste liquid disposal unit for treatment.

[0041] The hardness removal device and method for high-hardness salt-containing wastewater provided by the present invention can replace the traditional chemical softening method and cationic bed softening method for combined hardness removal, and achieve complete removal of high hardness. The regeneration liquid can use sodium sulfate solution, or a mixed solution of sodium sulfate and sodium chloride, or concentrated water from a membrane concentration system. The regenerated waste liquid can form calcium sulfate precipitation without adding any medicine, which greatly reduces the amount of hardness removal agent added. Compared with conventional hardness removal processes, the salt content of the system is greatly reduced; at the same time, the problem of calcium sulfate scale deposition and clogging caused by sodium sulfate as the regeneration liquid is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic diagram of the structure of a hardness removal device for high-hardness saline wastewater provided in an embodiment of the present invention;

[0043] Figure 2 A schematic flow chart of a method for removing hardness from high-hardness saline wastewater provided in an embodiment of the present invention;

[0044] Among them, 1-exchange column; 2-first regeneration column; 3-second regeneration column; 4-third regeneration column; 5-wash column; 6-water inlet tank; 7-water production tank; 8-first regeneration liquid tank; 9-second regeneration liquid tank; 10-third regeneration liquid tank; 11-regeneration waste liquid storage tank; 12-regeneration waste liquid primary sedimentation tank; 13-regeneration waste liquid secondary sedimentation tank; 14-compressed air storage tank; 15-water inlet pump; 16-wash column inlet pump; 17-grid flushing water pump; 18-first regeneration liquid pump; 19-second regeneration liquid pump; 20-third regeneration liquid pump; 21-sludge pump; 22-first Regeneration liquid tank agitator; 23-second regeneration liquid tank agitator; 24-third regeneration liquid tank agitator; 25-dosing system; 261-exchange column resin storage; 262-first resin storage; 263-second resin storage; 264-third resin storage; 265-fourth resin storage; 271-exchange column resin storage valve; 272-first resin storage valve; 273-second resin storage valve; 274-third resin storage valve; 275-fourth resin storage valve; 28-first resin grid; 29-second resin grid; 30-resin transfer pneumatic valve; 31-water inlet pipe; 32-exchange column inlet pipe; 33-exchange column outlet pipe; 34-water production tank main outlet pipe; 35-first grid flushing water pipe; 36-second grid flushing water pipe; 37-first regeneration liquid inlet pipe; 38-second regeneration liquid inlet pipe; 39-third regeneration liquid inlet pipe; 40-first regeneration liquid outlet pipe; 41-second regeneration liquid outlet pipe; 42-third regeneration liquid outlet pipe; 43-water washing outlet pipe; 44-first grid flushing waste water pipe; 45-second grid flushing waste water pipe; 46-compressed air pipe; 47-stirring Air mixing pipe; 48-resin transfer air pipe; 49-regeneration liquid main inlet pipe; 50-sludge pipe; 51-primary sedimentation tank outlet pipe; 52-regeneration liquid return pipe; 53-primary sedimentation tank sludge pump; 54-primary sedimentation tank sludge pipe; 55-sludge return pump; 56-sludge return pipe; 57-secondary sedimentation tank sludge pump; 58-secondary sedimentation tank sludge discharge pipe; 59-dosing pipe; 60-water washing inlet pipe; 61-first resin transfer pipe; 62-second resin transfer pipe; 63-third resin transfer pipe; 64-fourth resin transfer pipe; 65-fifth resin transfer pipe. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present invention will be further clearly and completely described below in conjunction with the drawings and embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0046] The inventor found in the research process of this embodiment that the patent document with publication number CN116750841A discloses a coal chemical production wastewater hardness removal system and method, wherein sodium ion exchange resin tanks connected in sequence are used to remove hardness from wastewater, and the sodium ion exchange resin tanks are regenerated using sulfate, and calcium ions in the regenerated waste liquid react with sulfate to generate calcium sulfate, forming gypsum solids, and the regenerated waste liquid is precipitated and recycled as regenerated liquid. The patent provides a system and method for removing hardness by sodium ion exchange resin, but fails to completely solve the problem of calcium sulfate scaling. The calcium sulfate deposited at the bottom of the precipitation separation tank will form calcium sulfate scale with high hardness, and gypsum solids need to be discharged regularly, which will consume a lot of manpower and material resources to achieve; in addition, during the recycling process of the regenerated waste liquid as the regenerated liquid after precipitation, the supernatant still contains high hardness, which will cause low resin regeneration rate, and then low resin utilization rate; magnesium ions in the regenerated waste liquid cannot be discharged from the system through precipitation separation, and will accumulate in the system; sodium ions and sulfate ions are constantly consumed during the regeneration process, so it is still necessary to continuously add regeneration agent to maintain the concentration of the regenerated liquid.

[0047] The innovation of the present invention lies in that it completely solves the problem of calcium sulfate scaling, and systematically and thoroughly treats and recycles the regeneration waste liquid. At the same time, magnesium ions will not accumulate in the system. The effluent from the treated regeneration waste liquid can be returned to, for example, the membrane concentrate and evaporation crystallization unit of the zero-emission system, thereby truly achieving the recycling of the regeneration liquid.

[0048] like Figure 1 , 2 As shown, an embodiment of the present invention provides a hardness removal device for high-hardness saline wastewater, the device comprising an exchange unit, a regeneration unit, and a regeneration waste liquid disposal unit, wherein:

[0049] The exchange unit comprises an exchange column 1, an inlet tank 6, a production water tank 7, and an inlet pump 15. After the wastewater is pre-treated at the front end to remove suspended solids, it enters the inlet tank 6. The inlet tank 6 is connected to the inlet pump 15 via a pipeline. The outlet pipe of the inlet pump is connected to the bottom water inlet of the exchange column 1 through the exchange column inlet pipe 32. The top water outlet of the exchange column 1 is connected to the production water tank 7 through the exchange column outlet pipe 33. The production water entering the production water tank 7 flows by gravity or pressure to the next treatment unit.

[0050] Specifically, an exchange column resin storage 261 is installed on the top of the exchange column 1, and an exchange column resin storage valve 271 is installed between the exchange column resin storage 261 and the top of the exchange column 1 to ensure that the amount of resin transferred into the exchange column 1 each time is a fixed value.

[0051] The bottom outlet of the exchange column 1 is connected to the regeneration unit through the first resin transfer pipe 61; the saturated resin in the lower layer of the exchange column 1 is transferred to the regeneration unit by gas lift, and the saturated resin is finally returned to the exchange column 1 after the regeneration and water washing of the resin are completed in the regeneration unit.

[0052] Optionally, the exchange column 1 adopts an intermittent moving bed or a continuous moving bed, the wastewater flows through the ion exchange resin from bottom to top in the exchange column 1, the ion exchange resin moves from top to bottom, the wastewater is in countercurrent contact with the ion exchange resin, and the calcium and magnesium ions in the wastewater are exchanged with the sodium ions on the ion exchange resin to achieve the effect of removing the hardness in the wastewater; the movement of the ion exchange resin in the exchange column 1 and the transfer between resin columns can be intermittent or continuous.

[0053] Optionally, the ion exchange resin is a sodium cationic resin, a macroporous resin, a gel resin, or a chelating resin. The particle size of the ion exchange resin is 95% of 0.1 mm to 3.0 mm, preferably 95% of 0.5 mm to 1.0 mm, and the grinding ball rate is ≥ 95%.

[0054] The resin described in this embodiment is a general term for resins in any state in the exchange column 1, the first regeneration column 2, the second regeneration column 3, the third regeneration column 4, and the water washing column 5. It can be a saturated resin formed after ion exchange, a primary regenerated resin obtained after a primary regeneration, a secondary regenerated resin obtained after a secondary regeneration, a tertiary regenerated resin obtained after a tertiary regeneration, or a regenerated resin obtained after water washing.

[0055] Optionally, the rising velocity of the wastewater in the exchange column 1 is less than 20 m / h, preferably 5 to 15 m / h; the residence time of the resin in the exchange column 1 is 2 to 8 h, preferably 3 to 6 h.

[0056] The regeneration unit includes a first regeneration column 2, a second regeneration column 3, a third regeneration column 4, a water washing column 5, a first regeneration liquid tank 8, a second regeneration liquid tank 9, a third regeneration liquid tank 10, a regeneration waste liquid storage tank 11, a compressed air storage tank 14, a water washing column inlet pump 16, a grid flushing water pump 17, a first regeneration liquid pump 18, a second regeneration liquid pump 19, a third regeneration liquid pump 20, a first regeneration liquid tank agitator 22, a second regeneration liquid tank agitator 23, a third regeneration liquid tank agitator 24, a first resin grid 28, and a second resin grid 29.

[0057] In the regeneration unit, countercurrent regeneration is used to improve the regeneration degree of the resin, that is, the resin to be regenerated (i.e., saturated resin) passes through the first regeneration column 2, the second regeneration column 3, and the third regeneration column 4 in sequence to complete the regeneration, and the regeneration liquid enters the third regeneration column 4 (primary regeneration liquid), the second regeneration column 3 (secondary regeneration liquid), and the first regeneration column 2 (tertiary regeneration liquid) in sequence to regenerate the resin. According to the density and particle size of the resin particles, the appropriate aeration and stirring intensity of the regeneration liquid is selected. The residence time of the tertiary regeneration liquid in the first regeneration column 2 is 2 to 10 hours, preferably 3 to 6 hours; in the second regeneration column 3, in order to make the resin in a fluidized or expanded suspension state, the secondary regeneration liquid has an upward flow rate of 15 to 30 m / h, and a suitable upward flow rate is selected according to the density and particle size of the resin particles; in the third regeneration column 4, in order to fully regenerate the resin, the primary regeneration liquid uses a low flow rate to regenerate the resin, and the primary regeneration liquid has an upward flow rate of less than 15 m / h, preferably 5 to 10 m / h; in the washing column 5, the resin is fully rinsed while reducing the amount of washing water, the washing water upward flow rate is less than 25 m / h, and a suitable upward flow rate is selected according to the density and particle size of the resin particles to ensure that the resin does not expand, preferably 10 to 20 m / h, and the amount of washing water is 1 to 2 times the amount of resin in the washing column 5. In the regeneration unit, the resin residence time is 8 to 16 hours, preferably 8 to 12 hours.

[0058] Specifically, the top of the first regeneration column 2 is connected to the first resin grid 28, the first resin storage 262, and the first resin storage valve 272 in sequence through pipelines from top to bottom. The bottom outlet of the exchange column 1 is connected to the first resin grid 28 at the top of the first regeneration column 2 through the first resin transfer pipe 61; the water inlet of the first resin grid 28 is connected to the outlet of the grid flushing water pump 17 through the first grid flushing water pipe 35, and the inlet of the grid flushing water pump 17 is connected to the water production tank 7 through a pipeline; the water outlet of the first resin grid 28 is connected to the flushing wastewater inlet of the water inlet tank 6 through the first grid flushing wastewater pipe 44.

[0059] Optionally, the first resin transfer pipe 61 is connected to the air outlet of the compressed air storage tank 14 through the resin transfer air pipe 48, and the compressed air storage tank 14 is used to supply air, and the saturated resin in the lower layer of the exchange column 1 is transferred to the first resin grid 28 through the first resin transfer pipe 61 by air lift; the saturated resin is washed in the first resin grid 28 by a small amount of produced water delivered by the grid washing water pump 17, and the waste water and suspended matter that may be entrained in the saturated resin can be removed, and then enters the first resin storage 262 to eliminate the influence of the waste water and the like entrained in the saturated resin on the first regeneration column 2. In a specific embodiment, by installing the first resin storage valve 272 below the first resin storage 262, it is ensured that the resin transfer amount entering the first regeneration column 2 each time is a fixed value.

[0060] Optionally, the air inlet at the bottom of the first regeneration column 2 is connected to the air outlet of the compressed air storage tank 14 through a stirring air pipe 47, so that the saturated resin in the first regeneration column 2 and the tertiary regeneration liquid are fully contacted by air stirring, while ensuring that the produced calcium sulfate precipitate will not be deposited in the resin column to form calcium sulfate scale; thereby, the materials (saturated resin, tertiary regeneration liquid) in the first regeneration column 2 are in a fluidized bed operation mode.

[0061] Optionally, a resin transfer pneumatic valve 30 is provided on the resin transfer air pipe 48 for opening and closing the resin transfer and adjusting the resin transfer air supply.

[0062] The outlet of the first regeneration liquid pump 18 is connected to the water inlet at the bottom of the first regeneration column 2 through the first regeneration liquid inlet pipe 37, and the inlet of the first regeneration liquid pump 18 is connected to the bottom of the first regeneration liquid tank 8; the water outlet at the top of the first regeneration column 2 is connected to the water inlet of the regeneration waste liquid storage tank 11 through the first regeneration liquid outlet pipe 40. The tertiary regeneration liquid in the first regeneration liquid tank 8 enters the first regeneration column 2 from the water inlet at the bottom of the first regeneration column 2, and countercurrently contacts with the saturated resin entering from the top of the first regeneration column 2, completing the primary regeneration of the saturated resin in the first regeneration column 2, and obtaining the primary regeneration resin. The regeneration waste liquid formed after the reaction of the tertiary regeneration liquid and the saturated resin enters the regeneration waste liquid storage tank 11 from the water outlet at the top of the first regeneration column 2 through the first regeneration liquid outlet pipe 40.

[0063] Since the calcium content in the saturated resin of the first regeneration column 2 is the highest in the regeneration unit, the calcium ions in the saturated resin react with the sulfate ions in the tertiary regeneration liquid to form calcium sulfate precipitates. The first regeneration column 2 adopts a fluidized bed operation mode, and most of the generated calcium sulfate can enter the regeneration waste liquid storage tank 11 along with the regeneration waste liquid; in addition, a small amount of calcium sulfate enters the second resin grid 29 along with the primary regeneration resin, and enters the regeneration waste liquid storage tank 11 after flushing, thereby avoiding calcium sulfate deposition and clogging the first regeneration column 2.

[0064] Optionally, considering the precipitation of calcium sulfate in the regeneration waste liquid in the regeneration waste liquid storage tank 11, a third regeneration liquid tank agitator 24 is installed in the regeneration waste liquid storage tank 11 to prevent the calcium sulfate in the regeneration waste liquid storage tank 11 from being deposited in the tank body.

[0065] Specifically, the top of the second regeneration column 3 is connected to the second resin grid 29, the second resin storage 263, and the second resin storage valve 273 in sequence from top to bottom through pipelines. The bottom outlet of the first regeneration column 2 is connected to the second resin grid 29 at the top of the second regeneration column 3 through the second resin transfer pipe 62; the water inlet of the second resin grid 29 is connected to the outlet of the grid flushing water pump 17 through the second grid flushing water pipe 36, and the inlet of the grid flushing water pump 17 is connected to the water production tank 7 through a pipeline; the water outlet of the second resin grid 29 is connected to the flushing wastewater inlet of the regeneration waste liquid storage tank 11 through the second grid flushing wastewater pipe 45. The lower layer resin of the first regeneration column 2 is transferred to the second resin grid 29 through the second resin transfer pipe 62, and the resin enters the second resin storage 263 after being flushed with a small amount of produced water.

[0066] Optionally, the second resin transfer pipe 62 is connected to the air outlet of the compressed air storage tank 14 through the resin transfer air pipe 48, and the compressed air storage tank 14 is used to supply air, and the first-level regeneration resin in the lower layer of the first regeneration column 2 is transferred to the second resin grid 29 through the second resin transfer pipe 62 by air lift; the first-level regeneration resin is washed in the second resin grid 29 by a small amount of produced water delivered by the grid washing water pump 17 to remove the calcium sulfate precipitate and the like entrained in the first-level regeneration resin, and then enters the second resin storage 263 to eliminate the influence of the calcium sulfate and the like entrained in the first-level regeneration resin on the first regeneration column 2. In a specific embodiment, by installing a second resin storage valve 273 below the second resin storage 263, it is ensured that the resin transfer amount entering the second regeneration column 3 each time is a fixed value.

[0067] Optionally, a resin transfer pneumatic valve 30 is provided on the resin transfer air pipe 48 for opening and closing the resin transfer and adjusting the resin transfer air supply.

[0068] The outlet of the second regeneration liquid pump 19 is connected to the water inlet at the bottom of the second regeneration column 3 through the second regeneration liquid inlet pipe 38, and the inlet of the second regeneration liquid pump 19 is connected to the bottom of the second regeneration liquid tank 9; the water outlet at the top of the second regeneration column 3 is connected to the water inlet of the first regeneration liquid tank 8 through the second regeneration liquid outlet pipe 41. The secondary regeneration liquid in the second regeneration liquid tank 9 enters the second regeneration column 3 from the water inlet at the bottom of the second regeneration column 3, and countercurrently contacts with the primary regeneration resin entering from the top of the second regeneration column 3, so as to realize the secondary regeneration of the primary regeneration resin in the second regeneration column 3 and obtain the secondary regeneration resin. The tertiary regeneration liquid formed after the reaction of the secondary regeneration liquid and the primary regeneration resin enters the first regeneration liquid tank 8 from the water outlet at the top of the second regeneration column 3 through the second regeneration liquid outlet pipe 41.

[0069] Optionally, the second regeneration column 3 adopts a fluidized bed operation mode, and the resin is put into a fluidized or suspended state by the high-speed rising flow rate of the secondary regeneration liquid entering from the bottom water inlet of the second regeneration column 3. A resin separation zone is set in the upper part of the second regeneration column 3, and the cross-sectional area of ​​the resin separation zone is enlarged to reduce the rising flow rate, thereby allowing the resin to return to the lower part of the resin separation zone.

[0070] Optionally, considering the precipitation of calcium sulfate in the tertiary regeneration liquid in the first regeneration liquid tank 8, a first regeneration liquid tank agitator 22 is installed in the first regeneration liquid tank 8 to prevent the calcium sulfate in the first regeneration liquid tank 8 from being deposited in the tank body.

[0071] Specifically, the top of the third regeneration column 4 is connected to the third resin storage 264 and the third resin storage valve 274 in sequence through pipelines from top to bottom. The bottom outlet of the second regeneration column 3 is connected to the third resin storage 264 at the top of the third regeneration column 4 through the third resin transfer pipe 63, and the lower layer resin of the second regeneration column 3 is transferred to the third resin storage 264 at the top of the third regeneration column 4 through the third resin transfer pipe 63.

[0072] Optionally, the third resin transfer pipe 63 is connected to the air outlet of the compressed air storage tank 14 through the resin transfer air pipe 48, and the compressed air storage tank 14 is used to supply air, and the secondary regeneration resin in the lower layer of the second regeneration column 3 is transferred to the third resin storage 264 through the third resin transfer pipe 63 by air lift; after the regeneration treatment of the first regeneration column 2 and the second regeneration column 3, 80-90% of the calcium and magnesium ions in the saturated resin have been replaced by the sodium ions in the regeneration liquid, and the calcium sulfate precipitate entrained in the secondary regeneration resin is also very small, so the secondary regeneration resin can directly enter the third regeneration column 4. In a specific embodiment, by installing a third resin storage valve 274 below the third resin storage 264, it is ensured that the resin transfer amount entering the third regeneration column 4 each time is a fixed value.

[0073] Optionally, a resin transfer pneumatic valve 30 is provided on the resin transfer air pipe 48 for opening and closing the resin transfer and adjusting the resin transfer air supply.

[0074] The outlet of the third regeneration liquid pump 20 is connected to the water inlet at the bottom of the third regeneration column 4 through the third regeneration liquid inlet pipe 39, and the inlet of the third regeneration liquid pump 20 is connected to the bottom of the third regeneration liquid tank 10; the water outlet at the top of the third regeneration column 4 is connected to the water inlet of the second regeneration liquid tank 9 through the third regeneration liquid outlet pipe 42; the regeneration liquid main inlet pipe 49 is connected to the water inlet of the third regeneration liquid tank 10. The regeneration liquid main inlet pipe 49 transports the primary regeneration liquid to the third regeneration liquid tank 10, and the primary regeneration liquid in the third regeneration liquid tank 10 enters the third regeneration column 4 from the water inlet at the bottom of the third regeneration column 4, and countercurrently contacts with the secondary regeneration resin entering from the top of the third regeneration column 4, and realizes the tertiary regeneration of the secondary regeneration resin in the third regeneration column 4, and obtains the tertiary regeneration resin. The secondary regeneration liquid formed after the primary regeneration liquid reacts with the secondary regeneration resin enters the second regeneration liquid tank 9 from the water outlet at the top of the third regeneration column 4 through the third regeneration liquid outlet pipe 42.

[0075] The total regeneration liquid inlet (primary regeneration liquid) transported by the regeneration liquid total inlet pipe 49 can be a sodium sulfate solution, a mixture of sodium sulfate and sodium chloride, or concentrated water from a membrane concentration system. Preferably, concentrated water from a membrane concentration system is used as the primary regeneration liquid. The sodium ion content in the primary regeneration liquid is greater than 15,000 mg / L, and the sulfate ion content is greater than 15,000 mg / L.

[0076] The main components of the membrane concentrated concentrated water are sodium sulfate, sodium chloride, and a small amount of other dissolved salts, organic matter, other impurities, etc.

[0077] Optionally, the third regeneration column 4 adopts an intermittent moving bed or a continuous moving bed, and the primary regeneration liquid enters from the bottom water inlet of the third regeneration column 4, flows through the secondary regeneration resin from bottom to top, and the secondary regeneration resin moves from top to bottom to complete the tertiary regeneration.

[0078] The third regeneration liquid tank 10 is provided with a second regeneration liquid tank agitator 23, which can play a stirring and dissolving role when a solid regeneration agent (such as solid sodium sulfate) is used to dissolve and prepare the regeneration liquid.

[0079] Specifically, the top of the water washing column 5 is connected to the fourth resin storage 265 and the fourth resin storage valve 275 in sequence through pipelines from top to bottom. The bottom outlet of the third regeneration column 4 is connected to the fourth resin storage 265 at the top of the water washing column 5 through the fourth resin transfer pipe 64, and the tertiary regeneration resin in the lower layer of the third regeneration column 4 is transferred to the fourth resin storage 265 through the fourth resin transfer pipe 64.

[0080] Optionally, the fourth resin transfer pipe 64 is connected to the air outlet of the compressed air storage tank 14 through the resin transfer air pipe 48, and the compressed air storage tank 14 is used to supply air, and the third-level regeneration resin in the lower layer of the third regeneration column 4 is transferred to the fourth resin storage 265 through the fourth resin transfer pipe 64 by air lift. The fourth resin storage valve 275 is installed below the fourth resin storage 265 to ensure that the transfer amount of the third-level regeneration resin entering the water washing column 5 each time is a fixed value. The bottom outlet of the water washing column 5 is connected to the exchange column resin storage 261 through the fifth resin transfer pipe 65, and the regeneration resin in the lower layer of the water washing column 5 is transferred to the resin storage 261 at the top of the exchange column 1 through the fifth resin transfer pipe 65.

[0081] The outlet of the washing column water inlet pump 16 is connected to the water inlet at the bottom of the washing column 5 through the washing water inlet pipe 60, and the inlet of the washing column water inlet pump 16 is connected to the washing water outlet of the water production tank 7 through a pipeline; the top outlet of the washing column 5 is connected to the washing outlet of the water inlet tank 6 through the washing water outlet pipe 43. The produced water in the water production tank 7 enters the washing column 5 from the bottom water inlet of the washing column 5, and countercurrently contacts with the tertiary regenerated resin entering from the top of the washing column 5, and washes the tertiary regenerated resin in the washing column 5 to remove the regeneration liquid entrained in the tertiary regenerated resin to obtain the regenerated resin. The washing liquid formed after the produced water washes the tertiary regenerated resin enters the water inlet tank 6 from the top outlet of the washing column 5 through the washing water outlet pipe 43.

[0082] In a specific embodiment, the bottom water inlets of the resin columns of the exchange column 1, the first regeneration column 2, the second regeneration column 3, the third regeneration column 4, and the water washing column 5 are all installed with rectifying devices to ensure uniform water distribution, and the upper water outlet areas of the resin columns of the exchange column 1, the first regeneration column 2, the second regeneration column 3, the third regeneration column 4, and the water washing column 5 adopt a perforated tubular stainless steel resin grid mesh that can increase the water flow area, and the grid mesh hole diameter is less than 95% of the minimum resin particle size.

[0083] In another specific embodiment, a liquid level meter or a material level meter is provided in the exchange column 1, the first regeneration column 2, the second regeneration column 3, the third regeneration column 4, and the water washing column 5. A liquid level meter is provided in the water inlet tank 6, the water production tank 7, the first regeneration liquid tank 8, the second regeneration liquid tank 9, the third regeneration liquid tank 10, and the regeneration waste liquid storage tank 11. An online conductivity meter is provided in the third regeneration liquid tank 10 to monitor the ion concentration in the primary regeneration liquid.

[0084] The regeneration waste liquid disposal unit includes a regeneration waste liquid primary sedimentation tank 12, a regeneration waste liquid secondary sedimentation tank 13, a sludge pump 21, and a dosing system 25. The outlet of the regeneration waste liquid storage tank 11 is connected to the inlet of the sludge pipe 50 through the sludge pump 21, the outlet of the sludge pipe 50 is connected to the water inlet of the regeneration waste liquid primary sedimentation tank 12, the outlet of the regeneration waste liquid primary sedimentation tank 12 is connected to the water inlet of the regeneration waste liquid secondary sedimentation tank 13 through the primary sedimentation tank outlet pipe 51, the outlet of the regeneration waste liquid secondary sedimentation tank 13 is connected to the regeneration liquid reflux pipe 52, and the regeneration liquid reflux pipe 52 is connected to the subsequent membrane concentration or evaporation crystallization unit. The primary sedimentation tank sludge discharge pipe 53 of the primary sedimentation tank 12 of the regenerated waste liquid is discharged to the sludge dewatering machine for dehydration treatment through the primary sedimentation tank sludge discharge pump 54; the sludge return pipe 56 of the secondary sedimentation tank is connected to the flocculation area of ​​the secondary sedimentation tank through the sludge return pump 55, and the secondary sedimentation tank sludge discharge pipe 58 is discharged to the sludge thickening system through the secondary sedimentation tank sludge discharge pump 57 for thickening and dehydration treatment; the dosing system 25 is connected to the coagulation area and flocculation area of ​​the secondary sedimentation tank 13 of the regenerated waste liquid through the dosing pipe 59.

[0085] Optionally, the regeneration waste liquid primary sedimentation tank 12 can adopt radial flow, horizontal flow, vertical flow, inclined plate (inclined tube) sedimentation tank. In a preferred embodiment, the regeneration waste liquid primary sedimentation tank 12 adopts a vertical flow sedimentation tank, a mud scraper is set at the bottom of the tank, mechanical mud is discharged, and a mud discharge pipe is set.

[0086] Optionally, the regeneration waste liquid secondary sedimentation tank 13 is dosing with a hardness removing agent, a coagulant, and a flocculant through a dosing system 25. The hardness removing agent is selected from one or a combination of sodium hydroxide, calcium hydroxide, and sodium carbonate; the coagulant is selected from one or a combination of aluminum sulfate, ferrous sulfate, ferric chloride, and basic aluminum chloride (PAC); the flocculant is preferably polyacrylamide (PAM).

[0087] Optionally, the secondary sedimentation tank 13 of the regenerated waste liquid is used for coagulation sedimentation and mud-water separation, wherein a coagulation reaction zone, a flocculation zone, and a sedimentation and clarification zone are set; the coagulation reaction zone can be multi-stage, and a coagulation agitator is set for the addition of hardness removal agents and coagulant agents; the flocculation agent is added to the flocculation zone, and a flocculation agitator is set in the flocculation zone; the sedimentation and clarification zone preferably adopts an inclined plate (inclined tube) sedimentation method, a scraper is set at the bottom of the tank, the sludge is discharged mechanically, and a sludge discharge pipe is set; a sludge return pipe 56 is set to allow the sludge to flow back to the flocculation zone.

[0088] like Figure 2 As shown, this embodiment also provides a method for removing hardness from high-hardness saline wastewater, which is implemented based on the hardness removal device for high-hardness saline wastewater, and the method includes the following steps:

[0089] S1. Ion exchange: The ion exchange resin enters the exchange column 1 from the exchange column resin storage 261, and the wastewater in the water inlet tank 6 is transported into the exchange column 1 from the water inlet at the bottom of the exchange column by the water inlet pump 15; when the wastewater flows through the exchange column 1 from bottom to top, it exchanges ions with the sodium ions on the ion exchange resin to remove the calcium and magnesium ions in the wastewater, and the hardness of the wastewater is removed to obtain the produced water, which enters the water production tank 7 from the top outlet of the exchange column 1 through the exchange column outlet pipe 33; the saturated resin formed by the ion exchange resin enters the regeneration unit for further regeneration.

[0090] Among them, the wastewater in the water inlet tank 6 is transported to the water inlet tank 6 after the high-hardness wastewater is removed of suspended matter by the pre-treatment unit.

[0091] Specifically, the amount of ion exchange resin entering the exchange column 1 from the exchange column resin storage 261 each time is controlled to be a fixed value by the exchange column resin storage valve 271 .

[0092] Specifically, the saturated resin is transferred from the bottom of the exchange column 1 along the first resin transfer pipe 61 to the first resin grid 28 at the top of the first regeneration column 2 by air stripping.

[0093] The exchange column 1 adopts an intermittent moving bed or a continuous moving bed, and the movement of the ion exchange resin in the exchange column 1 and the transfer between the exchange column 1, the first regeneration column 2, the second regeneration column 3, the third regeneration column 4, and the water washing column 5 can be intermittent or continuous.

[0094] Optionally, the rising velocity of the wastewater in the exchange column 1 is less than 20 m / h, preferably 5 to 15 m / h; the residence time of the resin in the exchange column 1 is 2 to 8 h, preferably 3 to 6 h.

[0095] S2. Resin regeneration: In the regeneration unit, the saturated resin passes through the first regeneration column 2, the second regeneration column 3, and the third regeneration column 4 in turn for primary regeneration, secondary regeneration, and tertiary regeneration. The primary regeneration liquid enters the third regeneration column 4 (primary regeneration liquid), the second regeneration column 3 (secondary regeneration liquid), and the first regeneration column 2 (tertiary regeneration liquid) in turn to regenerate the resin. A countercurrent regeneration method is used to improve the resin regeneration degree. The obtained regenerated resin is transferred to the exchange column resin storage 261 for ion exchange, and the formed regeneration waste liquid is transferred to the regeneration waste liquid disposal unit for treatment.

[0096] Optionally, in the regeneration unit, the resin residence time is 8 to 16 hours, preferably 8 to 12 hours.

[0097] Optionally, before the saturated resin enters the first regeneration column 2, it is washed with produced water in the first resin grid 28 at the top of the first regeneration column 2 to remove waste water, suspended matter, etc. that may be entrained in the saturated resin before entering the first resin storage 262. The first resin storage valve 272 controls the amount of resin transferred from the first resin storage 262 to the first regeneration column 2 each time to be a fixed value.

[0098] Specifically, the residence time of the tertiary regeneration liquid in the first regeneration column 2 is 2 to 10 hours; in a preferred embodiment, the residence time of the tertiary regeneration liquid in the first regeneration column 2 is 3 to 6 hours.

[0099] The tertiary regeneration liquid is transported from the first regeneration liquid tank 8 to the bottom water inlet of the first regeneration column 2 by the first regeneration liquid pump 18, and enters the first regeneration column 2, where it is countercurrently contacted with the saturated resin entering from the top of the first regeneration column 2 to complete the primary regeneration of the saturated resin; the obtained primary regeneration resin is transferred to the second resin grid 29 at the top of the second regeneration column 3 through the second resin transfer pipe 62; the regeneration waste liquid formed after the tertiary regeneration liquid reacts with the saturated resin is transported from the top water outlet of the first regeneration column 2 to the regeneration waste liquid storage tank 11.

[0100] Optionally, before the saturated resin enters the second regeneration column 3, it is rinsed with produced water in the second resin grid 29 at the top of the second regeneration column 3 to remove calcium sulfate precipitation and the like entrained in the primary regeneration resin before entering the second resin storage 263. The second resin storage valve 273 controls the amount of resin transferred from the second resin storage 263 to the second regeneration column 3 each time to be a fixed value.

[0101] Specifically, the rising velocity of the secondary regeneration liquid is 15-30 m / h to ensure that the resin is in a fluidized or expanded suspended state.

[0102] The secondary regeneration liquid is transported from the second regeneration liquid tank 9 to the bottom water inlet of the second regeneration column 3 by the second regeneration liquid pump 19, and enters the second regeneration column 3, where it is countercurrently contacted with the primary regeneration resin entering from the top of the second regeneration column 3, thereby completing the secondary regeneration of the primary regeneration resin; the obtained secondary regeneration resin is transferred to the third resin storage device 264 at the top of the third regeneration column 4 through the third resin transfer pipe 63; the tertiary regeneration liquid formed after the secondary regeneration liquid reacts with the primary regeneration resin is transported from the top water outlet of the second regeneration column 3 to the first regeneration liquid tank 8.

[0103] Optionally, the amount of resin transferred from the third resin storage 264 to the third regeneration column 4 each time is controlled to be a fixed value by the third resin storage valve 274. The first regeneration liquid in the third regeneration column 4 uses a low flow rate to regenerate the resin to ensure sufficient resin regeneration, and the first regeneration liquid rising flow rate is less than 15m / h; in a preferred embodiment, the first regeneration liquid rising flow rate is 5-10m / h.

[0104] The first-stage regeneration liquid is transported from the third regeneration liquid tank 10 to the bottom water inlet of the third regeneration column 4 by the third regeneration liquid pump 20, and enters the third regeneration column 4, where it is countercurrently contacted with the second-stage regeneration resin entering from the top of the third regeneration column 4, thereby completing the tertiary regeneration of the second-stage regeneration resin and obtaining the tertiary regeneration resin; the second-stage regeneration liquid formed after the first-stage regeneration liquid reacts with the second-stage regeneration resin is transported from the top water outlet of the third regeneration column 4 to the second regeneration liquid tank 9.

[0105] The primary regeneration liquid is transported to the third regeneration liquid tank 10 by the regeneration liquid main inlet pipe 49. The primary regeneration liquid is a sodium sulfate solution, a mixture of sodium sulfate and sodium chloride, or concentrated water from a membrane concentration system. The sodium ion content in the primary regeneration liquid is greater than 15000 mg / L, and the sulfate ion content is greater than 15000 mg / L.

[0106] Optionally, the resin regeneration in step S2 also includes a water washing step to remove the regeneration liquid entrained in the tertiary regeneration resin to obtain the regenerated resin. The tertiary regeneration resin obtained in the third regeneration column 4 is transferred to the fourth resin storage 265 at the top of the water washing column 5 through the fourth resin transfer pipe 64; the resin transfer amount from the fourth resin storage 265 to the water washing column 5 each time is controlled by the fourth resin storage valve 275 to be a fixed value. In the water washing column 5, the rising flow rate of the water washing water is less than 25m / h to ensure that the resin is fully rinsed while reducing the amount of water washing water; in a preferred embodiment, the rising flow rate of the water washing water is 10-20m / h, and the amount of water washing water is 1-2 times the amount of resin in the water washing column 5.

[0107] The produced water is transported from the water production tank 7 to the water inlet at the bottom of the water washing column 5 by the water washing column inlet pump 16, and enters the water washing column 5, where it is countercurrently contacted with the tertiary regenerated resin entering from the top of the water washing column 5 to complete the water washing of the tertiary regenerated resin. The obtained regenerated resin is transferred to the resin storage 261 at the top of the exchange column 1 through the fifth resin transfer pipe 65; the washing liquid formed after the produced water reacts with the tertiary regenerated resin is transported from the water outlet at the top of the water washing column 5 to the water inlet tank 6.

[0108] S3. Regeneration waste liquid disposal: The regeneration waste liquid in the regeneration waste liquid storage tank 11 is processed in turn by the regeneration waste liquid primary sedimentation tank 12 and the regeneration waste liquid secondary sedimentation tank 13, and then enters the subsequent membrane concentration or evaporation crystallization unit.

[0109] Optionally, the regeneration waste liquid primary sedimentation tank 12 can adopt radial flow, horizontal flow, vertical flow, inclined plate (inclined tube) sedimentation tank. In a preferred embodiment, the regeneration waste liquid primary sedimentation tank 12 adopts a vertical flow sedimentation tank, a mud scraper is set at the bottom of the tank, mechanical mud is discharged, and a mud discharge pipe is set.

[0110] Optionally, the regeneration waste liquid secondary sedimentation tank 13 is dosing with a hardness removing agent, a coagulant, and a flocculant through a dosing system 25. The hardness removing agent is selected from one or a combination of sodium hydroxide, calcium hydroxide, and sodium carbonate; the coagulant is selected from one or a combination of aluminum sulfate, ferrous sulfate, ferric chloride, and basic aluminum chloride (PAC); the flocculant is preferably polyacrylamide (PAM).

[0111] Optionally, the secondary sedimentation tank 13 of the regenerated waste liquid is used for coagulation sedimentation and mud-water separation, wherein a coagulation reaction zone, a flocculation zone, and a sedimentation and clarification zone are set; the coagulation reaction zone can be multi-stage, and a coagulation agitator is set for the addition of hardness removal agents and coagulant agents; the flocculation agent is added to the flocculation zone, and a flocculation agitator is set in the flocculation zone; the sedimentation and clarification zone preferably adopts an inclined plate (inclined tube) sedimentation method, a scraper is set at the bottom of the tank, the sludge is discharged mechanically, and a sludge discharge pipe is set; a sludge return pipe 56 is set to allow the sludge to flow back to the flocculation zone.

[0112] Example:

[0113] The following is a pilot project implemented in a coal chemical plant as an example to describe in detail the hardness removal device and method for high-hardness salt-containing wastewater provided by the embodiment of the present invention. This embodiment is used to illustrate the present invention, but is not used to limit the scope of the present invention.

[0114] Influent water quality: total hardness (calculated as calcium carbonate) is 500-1500 mg / L, TDS is 4000-7000 mg / L.

[0115] Outlet water quality: total hardness (calculated as calcium carbonate) <10mg / L.

[0116] The process flow and conditions for treating the above-mentioned project by using the hardness removal device and method for high-hardness salt-containing wastewater are as follows:

[0117] After coagulation and sedimentation, and filtration to remove suspended solids, the high-hardness wastewater enters the exchange column 1 from the bottom of the exchange column. The wastewater flows through the exchange column from bottom to top, and the wastewater after the hardness is removed enters the subsequent treatment unit;

[0118] The saturated resin in the lower layer of the exchange column 1 is transferred to the first regeneration column 2 by gas stripping and enters the resin regeneration unit;

[0119] The resin is regenerated by countercurrent regeneration, that is, the saturated resin passes through the first regeneration column 2, the second regeneration column 3, and the third regeneration column 4 in sequence, and the regeneration liquid passes through the third regeneration column 4, the second regeneration column 3, and the first regeneration column 2 in sequence; the regenerated resin obtained after the tertiary regenerated resin is washed with water in the water washing column 5 returns to the exchange column 1 again for the next cycle of exchange.

[0120] The exchange column 1 adopts an intermittent moving bed, with water continuously entering. The wastewater flows through the resin from bottom to top in the column, and the resin moves from top to bottom. The movement of the resin in the exchange column 1 and the transfer between the resin columns are intermittent, and the transfer is once every 1 to 2 hours. The resin transfer is controlled by time, and the resin transfer amount is controlled by a level meter or a liquid level meter in the resin column to keep the resin and liquid level in the resin column in a balanced state; the first regeneration column 2 adopts a fluidized bed, the second regeneration column 3 adopts a fluidized bed, and the third regeneration column 4 adopts an intermittent moving bed; the first regeneration column 2, the second regeneration column 3, the third regeneration column 4, and the water washing column 5 in the regeneration unit can work simultaneously, and the resin exchange and regeneration are ensured to be carried out simultaneously by reasonably setting the operating time and operating sequence.

[0121] The resin adopts sodium cationic macroporous resin, the particle size range of the resin is 95% of the resin particle size is 0.5mm ~ 1.2mm, and the infiltration ball rate is ≥ 95%;

[0122] The total inlet liquid of the regeneration liquid is the concentrated water of the membrane of the plant's zero emission system. The sodium ion content in the regeneration liquid is 17000-18000 mg / L, and the sulfate ion content is 33000-35000 mg / L.

[0123] The primary sedimentation tank for the regenerated waste liquid adopts a vertical flow, inclined plate (inclined tube) sedimentation tank, with a scraper installed at the bottom of the tank for mechanical sludge discharge.

[0124] The secondary sedimentation tank for regenerated waste liquid is equipped with a first mixing zone, a second mixing zone, a flocculation zone and an inclined tube sedimentation zone. Sodium hydroxide and basic aluminum chloride (PAC) are added to the first mixing zone, sodium carbonate is added to the second mixing zone, and polyacrylamide (PAM) is added to the flocculation zone. A scraper is installed at the bottom of the tank for mechanical sludge discharge, and 5-10% of the sludge is returned to the flocculation zone.

[0125] Agitators are provided in the first regeneration liquid tank 8 and the regeneration waste liquid storage tank 11 to prevent the regeneration liquid and the regeneration waste liquid from settling in the tank body; liquid level gauges are provided in the water inlet tank 6, the water production tank 7, the first regeneration liquid tank 8, the second regeneration liquid tank 9, the third regeneration liquid tank 10 and the regeneration waste liquid storage tank 11 for controlling the liquid level when the water pump is started and stopped; an online conductivity meter is provided in the third regeneration liquid tank 10 to monitor the ion concentration in the primary regeneration liquid.

[0126] The reagent cost of the pilot project described in this embodiment is about 1 yuan / ton, which saves 4 to 5 yuan / ton compared with chemical hardness removal.

[0127] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A hardness removal device for high-hardness saline wastewater. It is characterized in that The device comprises an exchange unit, a regeneration unit, and a regeneration waste liquid disposal unit, wherein: The exchange unit comprises an exchange column, a water inlet tank, a water production tank, and a water inlet pump. The water inlet tank is connected to the water inlet at the bottom of the exchange column through the water inlet pump, and the water outlet at the top of the exchange column is connected to the water production tank through the exchange column outlet pipe; an exchange column resin storage is installed on the top of the exchange column; The regeneration unit comprises a first regeneration column, a second regeneration column, a third regeneration column, a water washing column, a first regeneration liquid tank, a second regeneration liquid tank, a third regeneration liquid tank, a regeneration waste liquid storage tank, a compressed air storage tank, a first regeneration liquid pump, a second regeneration liquid pump, a third regeneration liquid pump, and a water washing column water inlet pump; The top of the first regeneration column is connected to the first resin grid and the first resin storage tank through pipelines from top to bottom, and the bottom outlet of the exchange column is connected to the first resin grid through the first resin transfer pipe; the bottom water inlet of the first regeneration column is connected to the first regeneration liquid tank through the first regeneration liquid pump, and the top water outlet of the first regeneration column is connected to the water inlet of the regeneration waste liquid storage tank; The top of the second regeneration column is connected to the second resin grid and the second resin storage via pipelines from top to bottom, and the bottom outlet of the first regeneration column is connected to the second resin grid via a second resin transfer pipe; The water inlet at the bottom of the second regeneration column is connected to the second regeneration liquid tank through the second regeneration liquid pump, and the water outlet at the top of the second regeneration column is connected to the water inlet of the first regeneration liquid tank; The third regeneration column is connected to the third resin storage via a pipeline, and the bottom outlet of the second regeneration column is connected to the third resin storage via a third resin transfer pipe; the bottom water inlet of the third regeneration column is connected to the third regeneration liquid tank via a third regeneration liquid pump, and the top water outlet of the third regeneration column is connected to the water inlet of the second regeneration liquid tank; The water washing column is connected to the fourth resin storage via a pipeline, and the bottom outlet of the third regeneration column is connected to the fourth resin storage at the top of the water washing column via a fourth resin transfer pipe; the water inlet at the bottom of the water washing column is connected to the water production tank via a water washing column water inlet pump, and the water outlet at the top of the water washing column is connected to the water inlet tank; the bottom outlet of the water washing column is connected to the exchange column resin storage via a fifth resin transfer pipe; The first resin transfer pipe, the second resin transfer pipe, the third resin transfer pipe, and the fourth resin transfer pipe are respectively connected to the air outlet of the compressed air storage tank; The regeneration waste liquid disposal unit includes a primary sedimentation tank for regeneration waste liquid, a secondary sedimentation tank for regeneration waste liquid, a sludge pump, and a dosing system; the outlet of the regeneration waste liquid storage tank is connected to the water inlet of the primary sedimentation tank for regeneration waste liquid through a sludge pump, and the water outlet of the primary sedimentation tank for regeneration waste liquid is connected to the water inlet of the secondary sedimentation tank for regeneration waste liquid; the dosing system is connected to the coagulation zone and flocculation zone of the secondary sedimentation tank for regeneration waste liquid; the outlet of the secondary sedimentation tank for regeneration waste liquid is connected to the subsequent membrane concentration or evaporation crystallization unit through a regeneration liquid reflux pipe.

2. A hardness removal device for high-hardness saline wastewater according to claim 1, It is characterized in that The first resin grid water inlet is connected to the water production tank through a grid flushing water pump; the first resin grid water outlet is connected to the flushing wastewater inlet of the water inlet tank through a first grid flushing wastewater pipe; The water inlet of the second resin grid is connected to the water production tank through a grid flushing water pump; The second resin grid water outlet is connected to the regeneration waste liquid storage tank flushing waste water inlet through the second grid flushing waste water pipe.

3. A hardness removal device for high-hardness saline wastewater according to claim 1, It is characterized in that The regeneration unit also includes a first regeneration liquid tank agitator installed in the first regeneration liquid tank; the regeneration unit also includes a second regeneration liquid tank agitator installed in the third regeneration liquid tank; the regeneration unit also includes a third regeneration liquid tank agitator installed in the regeneration waste liquid storage tank.

4. A hardness removal device for high-hardness saline wastewater according to claim 1, It is characterized in that An exchange column resin storage valve is installed between the exchange column resin storage and the top of the exchange column; A first resin storage valve is installed between the first regeneration column and the first resin storage; A second resin storage valve is installed between the second regeneration column and the second resin storage; A third resin storage valve is installed between the third regeneration column and the third resin storage; A fourth resin storage valve is installed between the water washing column and the fourth resin storage.

5. A hardness removal device for high-hardness saline wastewater according to claim 1, It is characterized in that The air inlet at the bottom of the first regeneration column is connected to the air outlet of the compressed air storage tank through a stirring air pipe.

6. A hardness removal device for high-hardness saline wastewater according to claim 1, It is characterized in that The first resin transfer pipe, the second resin transfer pipe, the third resin transfer pipe, and the fourth resin transfer pipe are respectively connected to the air outlet of the compressed air storage tank through the resin transfer air pipe; The resin transfer air pipe is provided with a resin transfer pneumatic valve.

7. A method for removing hardness from high-hardness saline wastewater. It is characterized in that The method is realized based on the hardness removal device for high-hardness salt-containing wastewater according to any one of claims 1 to 6, and the method comprises the following steps: S1. Ion exchange: The ion exchange resin enters the exchange column from the exchange column resin storage, and the wastewater in the water inlet tank is transported into the exchange column from the water inlet at the bottom of the exchange column by the water inlet pump; when the wastewater flows through the exchange column from bottom to top, it exchanges ions with the sodium ions on the ion exchange resin, and the hardness of the wastewater is removed to obtain the produced water, which enters the water production tank from the water outlet at the top of the exchange column through the exchange column outlet pipe; the saturated resin formed by the ion exchange resin enters the regeneration unit for regeneration; S2. Resin regeneration: In the regeneration unit, the saturated resin passes through the first regeneration column, the second regeneration column, and the third regeneration column in sequence for primary regeneration, secondary regeneration, and tertiary regeneration. The primary regeneration liquid enters the third regeneration column, the second regeneration column, and the first regeneration column in sequence to regenerate the resin. A countercurrent regeneration method is used to improve the resin regeneration degree. The obtained regenerated resin is transferred to the exchange column resin storage for ion exchange, and the generated regeneration waste liquid is transferred to the regeneration waste liquid disposal unit for treatment; S3. Regeneration waste liquid disposal: The regeneration waste liquid in the regeneration waste liquid storage tank is processed in turn through the regeneration waste liquid primary sedimentation tank and the regeneration waste liquid secondary sedimentation tank.

8. The method for removing hardness from high-hardness saline wastewater according to claim 7, It is characterized in that In step S2, the saturated resin is sequentially passed through the first regeneration column, the second regeneration column, and the third regeneration column for primary regeneration, secondary regeneration, and tertiary regeneration, and then needs to undergo a water washing step to obtain the regenerated resin.

9. A method for removing hardness from high-hardness saline wastewater according to claim 7, It is characterized in that The exchange column adopts an intermittent moving bed or a continuous moving bed; The rising velocity of wastewater in the exchange column is 5 to 15 m / h; the residence time of the resin in the exchange column is 2 to 8 hours.

10. A method for removing hardness from high-hardness saline wastewater according to claim 7, It is characterized in that In the regeneration unit, the resin residence time is 8 to 16 hours; The first regeneration column uses a fluidized bed, and the residence time of the tertiary regeneration liquid in the first regeneration column is 2 to 10 hours; The second regeneration column uses a fluidized bed, and the rising velocity of the secondary regeneration liquid is 15-30m / h; The third regeneration column adopts an intermittent moving bed or a continuous moving bed, and the rising flow rate of the first-stage regeneration liquid is 5 to 10 m / h.

11. A method for removing hardness from high-hardness saline wastewater according to claim 7, It is characterized in that The primary regeneration liquid is a sodium sulfate solution, or a mixture of sodium sulfate and sodium chloride, or concentrated water from a membrane concentration system; In the primary regeneration liquid, the sodium ion content is greater than 15000 mg / L, and the sulfate ion content is greater than 15000 mg / L.

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