Treatment device for high-hardness and high-salinity wastewater

Abstract

The utility model relates to the technical field of wastewater treatment, and discloses a high-hardness and high-salinity wastewater treatment device which comprises a seed crystal fluidization tank, a medicament storage tank, a crystallization and granulation fluidized bed and a multi-effect evaporation system, the crystallization and granulation fluidized bed is respectively connected with the seed crystal fluidization tank and the medicament storage tank through pipelines, and the multi-effect evaporation system is connected with the seed crystal fluidization tank and the medicament storage tank through pipelines. The liquid inlet position of the multi-effect evaporation system is connected with a liquid outlet end pipeline of the crystallization and granulation fluidized bed, the liquid return position of the multi-effect evaporation system is connected with a liquid inlet end pipeline of the crystallization and granulation fluidized bed, the air outlet end of the multi-effect evaporation system is connected with a condenser through a pipeline, and the condenser is connected with a vacuum pump through a pipeline; the liquid return position of the multi-effect evaporation system is externally connected with high-hardness and high-salinity wastewater, and the high-hardness and high-salinity wastewater can be mixed with return liquid flowing out of the liquid return position of the multi-effect evaporation system and then enters the liquid inlet end of the crystallization and granulation fluidized bed; the device has the advantages that the occupied area is reduced, and the operation cost is reduced.

Description

Technical Field

[0001] The utility model relates to a device for treating high-hardness and high-salt wastewater, belonging to the technical field of wastewater treatment. Background Art

[0002] At present, the existing methods for treating high-hardness and high-salt wastewater include the following: the first method: direct evaporation and concentration into salt; the second method: no pretreatment, direct use of multiple-effect evaporation; the third method: pretreatment with chemical softening and then separation of water and salt by multiple-effect evaporation.

[0003] However, the above treatment methods have the following problems: The first method uses direct evaporation and concentration to form salts, which has the problems of low heat source utilization efficiency, high heat consumption, high operating cost, easy scaling of nozzles and other components, and complex salt components of produced water that cannot be recycled; the second method does not do pretreatment and directly uses multi-effect evaporation to treat the water. Although it can save heating steam consumption and reduce operating costs by using the secondary steam of the first effect as the heating agent of the second effect, when treating high-hardness wastewater, it does not remove the hardness of the wastewater first, so the heater coil is prone to scaling, affecting the heat exchange efficiency and the amount of water treated. The third method uses chemical softening for pretreatment and then multi-effect evaporation. If the pretreatment uses the traditional chemical method for softening, there is a problem of high chemical consumption and low utilization rate. At the same time, the produced water needs to be acidified to adjust the pH, which will bring in a large amount of chloride ions or sulfate ions, resulting in a large amount of sludge that needs to be treated. If the pretreatment uses the crystallization granulation fluidized bed method, the treated water volume is less than 50m 3 / h, the tower diameter is less than 800mm and the tower wall is prone to scaling. When the hardness is higher than 1500mg / L, the calcium carbonate crystals generated by the dosing reaction are prone to self-nucleation and cannot adhere to the surface of the seed crystals to grow, resulting in high turbidity of the effluent and requiring a large cost to treat the wastewater.

[0004] The invention patent with Chinese patent authorization announcement number CN105152435B provides a zero-discharge treatment method for wastewater containing high-concentration active salts. It uses evaporation and crystallization technology to treat concentrated water discharged from the RO system, thereby achieving zero-discharge treatment of wastewater containing high-concentration salts. However, it does not integrate crystallization granulation and multi-effect evaporation, and corresponding improvements can be made. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the utility model provides a treatment device for high-hardness and high-salt wastewater.

[0006] The technical solution of the utility model is as follows:

[0007] In the first aspect, the utility model provides a treatment device for high-hardness and high-salt wastewater, comprising a seed fluidized bed, a reagent storage tank and a crystallization granulation fluidized bed, wherein the crystallization granulation fluidized bed is respectively connected to the seed fluidized tank and the reagent storage tank through pipes, and the treatment device also comprises a multiple-effect evaporation system, wherein the liquid inlet of the multiple-effect evaporation system is connected to the liquid outlet pipe of the crystallization granulation fluidized bed, the liquid return of the multiple-effect evaporation system is connected to the liquid inlet pipe of the crystallization granulation fluidized bed, the gas outlet pipe of the multiple-effect evaporation system is connected to a condenser, and the condenser pipe is connected to a vacuum pump; the liquid return of the multiple-effect evaporation system is also externally connected to high-hardness and high-salt wastewater, and the high-hardness and high-salt wastewater can be mixed with the return liquid flowing out from the liquid return of the multiple-effect evaporation system and then enter the liquid inlet of the crystallization granulation fluidized bed.

[0008] Furthermore, the multiple-effect evaporation system comprises a first-effect heater, a first-effect separator, a second-effect heater and a second-effect separator, and the multiple-effect evaporation system is used for performing rising film evaporation or falling film evaporation.

[0009] Furthermore, the liquid outlet of the crystallization granulation fluidized bed is respectively connected to the bottom port of the first-effect heater and the bottom port of the second-effect heater by pipelines, the top port of the first-effect heater is connected to the feed end pipeline of the first-effect separator, the side air inlet of the first-effect heater is connected to the heat source steam by pipeline, the liquid outlet of the first-effect separator is connected to the liquid inlet end pipeline of the crystallization granulation fluidized bed, the air outlet of the first-effect separator is connected to the side air inlet pipeline of the second-effect heater, the top port of the second-effect heater is connected to the feed end pipeline of the second-effect separator, the side air outlet of the second-effect heater is connected to the condenser by pipeline, the liquid outlet of the second-effect separator is respectively connected to the bottom port of the second-effect heater and the external dehydration and drying system pipeline, and the air outlet of the second-effect separator is connected to the condenser by pipeline.

[0010] Furthermore, a first-effect forced circulation pump is provided on the pipeline connecting the liquid outlet of the first-effect separator and the liquid inlet of the crystallization granulation fluidized bed, and the pipeline connecting the high-hardness and high-salt wastewater and the liquid inlet of the crystallization granulation fluidized bed passes through the first-effect forced circulation pump.

[0011] Furthermore, a second-effect forced circulation pump is arranged on the pipeline connecting the liquid outlet of the crystallization granulation fluidized bed and the bottom port of the second-effect heater, and the pipeline connecting the liquid outlet of the second-effect separator and the bottom port of the second-effect heater passes through the second-effect forced circulation pump.

[0012] Furthermore, the liquid outlet of the crystallization granulation fluidized bed is connected to the top port pipeline of the first-effect heater, the bottom port of the first-effect heater is connected to the liquid inlet end pipeline of the crystallization granulation fluidized bed, the side port of the first-effect heater is connected to the feed end pipeline of the first-effect separator, the side air inlet pipeline of the first-effect heater is connected with heat source steam, the liquid outlet of the first-effect separator is respectively connected to the liquid inlet end of the crystallization granulation fluidized bed and the top port pipeline of the second-effect heater, the air outlet of the first-effect separator is connected to the side air inlet pipeline of the second-effect heater, the bottom port of the second-effect heater is connected to the top port pipeline of the second-effect heater, the side port of the second-effect heater is connected to the feed end pipeline of the second-effect separator, the liquid outlet of the second-effect separator is respectively connected to the top port of the second-effect heater and the external dehydration and drying system pipeline, and the air outlet of the second-effect separator is connected to the condenser by pipeline.

[0013] Furthermore, a first-effect forced circulation pump is provided on the pipeline connecting the bottom port of the first-effect heater and the liquid inlet end of the crystallization granulation fluidized bed, and the pipeline connecting the liquid outlet end of the first-effect separator and the liquid inlet end of the crystallization granulation fluidized bed and the pipeline connecting the high-hardness and high-salt wastewater and the liquid inlet end of the crystallization granulation fluidized bed both pass through the first-effect forced circulation pump.

[0014] Furthermore, a second-effect forced circulation pump is arranged on the pipeline connecting the liquid outlet end of the first-effect separator and the top port of the second-effect heater, and the pipeline connecting the bottom port of the second-effect heater and the top port of the second-effect heater and the pipeline connecting the liquid outlet end of the second-effect separator and the top port of the second-effect heater both pass through the second-effect forced circulation pump.

[0015] Furthermore, a seed dosing pump is provided on the pipeline connecting the feed end of the crystallization granulation fluidized bed with the seed fluidization tank, and a drug dosing pump is provided on the pipeline connecting the drug feed end of the crystallization granulation fluidized bed with the drug storage tank.

[0016] In a second aspect, the utility model provides a method for using the aforementioned high-hardness and high-salt wastewater treatment device, comprising the following steps:

[0017] The first step: adding seed crystals into the seed fluidization tank, then feeding fluidizing water into the bottom of the seed fluidization tank to fluidize the seed crystals in the seed fluidization tank, starting the seed crystal adding pump, and the seed crystal adding pump adds the fluidized seed crystals in the seed fluidization tank into the crystallization granulation fluidized bed for crystallization granulation;

[0018] Step 2: Start the first-effect forced circulation pump to allow the wastewater generated by crystallization and granulation to enter the multi-effect evaporation system for circulation, start the reagent dosing pump, and start the reagent dosing pump. The reagent dosing pump adds the alkaline reagent in the reagent storage tank into the crystallization and granulation fluidized bed to react with the mixed high-hardness and high-salt wastewater to remove hardness ions;

[0019] Step 3: introducing heat source steam into the multiple-effect evaporation system, so that the multiple-effect evaporation system heats and evaporates the incoming wastewater, and the reflux water flowing out of the reflux point of the multiple-effect evaporation system is mixed with the high-hardness and high-salt incoming water, and the mixed high-hardness and high-salt incoming water enters the liquid inlet end of the crystallization granulation fluidized bed;

[0020] Step 4: Start the second-effect forced circulation pump and the vacuum pump to circulate inside the multiple-effect evaporation system and discharge gas, condensed water and high-salt water.

[0021] The utility model has the following beneficial effects:

[0022] The utility model integrates crystallization and granulation with multiple-effect evaporation, so that the treatment device can simultaneously perform crystallization and granulation to remove hardness during the multiple-effect evaporation concentration process. In the production process, the wastewater separated by the single-effect separator can be mixed with high-hardness and high-salt wastewater, which can have the following effects:

[0023] 1. It can reduce the hardness of wastewater entering the crystallization granulation fluidized bed, reduce the self-nucleation of calcium carbonate crystals, make calcium carbonate grow on the crystal seeds, ensure low turbidity of hard water, and do not need to set up sedimentation and sludge dewatering system.

[0024] 2. The inlet water temperature can be increased, thereby reducing the solubility of calcium carbonate, reducing the reagent concentration required for the reaction, saving reagents and reducing operating costs.

[0025] 3. High-salt and high-hardness incoming water usually has a small amount of water. After mixing with the reflux water, it enters the crystallization granulation fluidized bed, which can increase the water flow rate entering the crystallization granulation fluidized bed and avoid the situation where the tower diameter is too small and the tower wall is easy to scale when the flow rate is small.

[0026] 4. It makes full use of the advantages of multi-effect evaporation, high efficiency and energy saving, and reduces the operating cost of the evaporation and concentration process.

[0027] 5. Using crystallization granulation to remove hardness also extends the operating cycle of the multi-effect evaporation system and reduces the cost of descaling the heat exchanger coil.

[0028] At the same time, the gas discharged from the top of the second-effect separator can be condensed by the condenser and reused as high-quality water, and the liquid at the bottom of the second-effect separator can produce product salt after passing through the subsequent dehydration and drying system to achieve zero emissions. Compared with the existing technology, it has the advantages of reducing floor space and lowering operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the structure of the utility model in the rising film evaporation mode;

[0030] Figure 2This is a schematic diagram of the structure of the utility model in the falling film evaporation mode.

[0031] The reference numerals in the figure represent:

[0032] 1. Seed fluidizing tank; 2. Reagent storage tank; 3. Crystallization granulation fluidized bed; 4. Condenser; 5. Vacuum pump; 6. First-effect heater; 7. First-effect separator; 8. Second-effect heater; 9. Second-effect separator; 10. First-effect forced circulation pump; 11. Second-effect forced circulation pump; 12. Seed dosing pump; 13. Reagent dosing pump. DETAILED DESCRIPTION

[0033] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Example 1: Please refer to Figure 1 The present example provides a treatment device for high-hardness and high-salt wastewater, comprising a seed fluidizing tank 1, a reagent storage tank 2 and a crystallization granulation fluidized bed 3, wherein the seed fluidizing tank 1 is filled with required seed crystals, the reagent storage tank 2 is filled with required alkaline reagents, the feed end of the crystallization granulation fluidized bed 3 is connected with a pipeline of the seed fluidizing tank 1, a seed dosing pump 12 is arranged on the pipeline connecting the feed end of the crystallization granulation fluidized bed 3 with the discharge end of the seed fluidizing tank 1, the seed dosing pump 12 can pump the seed crystals in the seed fluidizing tank 1 into the crystallization granulation fluidized bed 3, the drug feed end of the crystallization granulation fluidized bed 3 is connected with a pipeline of the reagent storage tank 2, a reagent dosing pump 13 is arranged on the pipeline connecting the drug feed end of the crystallization granulation fluidized bed 3 with the discharge end of the reagent storage tank 2, the reagent dosing pump 13 can pump the reagent in the reagent storage tank 2 into the crystallization granulation fluidized bed 3.

[0035] The treatment device also includes a multiple-effect evaporation system, the liquid inlet of the multiple-effect evaporation system is connected to the liquid outlet pipe of the crystallization granulation fluidized bed 3, the liquid return of the multiple-effect evaporation system is connected to the liquid inlet pipe of the crystallization granulation fluidized bed 3, the gas outlet pipe of the multiple-effect evaporation system is connected to a condenser 4, and the pipe on the condenser 4 is connected to a vacuum pump 5; the liquid return of the multiple-effect evaporation system is also externally connected to high-hardness and high-salt wastewater, and the high-hardness and high-salt wastewater can be mixed with the return liquid flowing out from the liquid return of the multiple-effect evaporation system and then enter the liquid inlet of the crystallization granulation fluidized bed 3.

[0036] In this embodiment, the multi-effect evaporation system is a rising film evaporation, and the multi-effect evaporation system includes a first-effect heater 6, a first-effect separator 7, a second-effect heater 8 and a second-effect separator 9. The liquid outlet of the crystallization granulation fluidized bed 3 is respectively connected to the bottom port of the first-effect heater 6 and the bottom port of the second-effect heater 8 by pipelines, so that the wastewater discharged from the liquid outlet of the crystallization granulation fluidized bed 3 can enter the first-effect heater 6 and the second-effect heater 8 for heating and evaporation. At the same time, the first-effect separator 7 can be arranged above the crystallization granulation fluidized bed 3 to save the required floor space.

[0037] The top port of the first-effect heater 6 is connected to the feed end pipeline of the first-effect separator 7. The wastewater heated by the first-effect heater 6 can enter the first-effect separator 7 for flash evaporation. The pipeline on the side air inlet of the first-effect heater 6 is connected to the heat source steam, and the heat source steam provides the required heat source for the heating and evaporation work of the first-effect heater 6.

[0038] The liquid outlet of the first-effect separator 7 is connected to the liquid inlet pipeline of the crystallization granulation fluidized bed 3, and the high-temperature water remaining after flash separation by the first-effect separator 7 can flow back to the crystallization granulation fluidized bed 3 through this pipeline. A first-effect forced circulation pump 10 is arranged on the pipeline connecting the liquid outlet of the first-effect separator 7 and the liquid inlet of the crystallization granulation fluidized bed 3, and the pipeline connecting the high-hardness and high-salt wastewater and the liquid inlet of the crystallization granulation fluidized bed 3 passes through the first-effect forced circulation pump 10, so that the high-hardness and high-salt wastewater can be mixed with the reflux water with high temperature, so as to increase the water inlet temperature of the high-hardness and high-salt wastewater entering the crystallization granulation fluidized bed 3, so as to reduce the solubility of calcium carbonate and the supersaturation required for crystallization, so as to reduce the subsequent dosage of the reagent and reduce the operating cost. At the same time, it can also reduce the occurrence of self-nucleation of calcium carbonate crystals, so that calcium carbonate grows on the seed crystals, ensuring the low turbidity of the hardness-removed water, and there is no need to set up a sedimentation and sludge dehydration system. In addition, after the high-hardness and high-salt wastewater is mixed with the reflux water, the inlet and outlet water flow rate of the crystallization granulation fluidized bed 3 can be increased, avoiding the situation that the tower diameter is too small and the tower wall is easy to scale when the flow rate is small. The water after the crystallization granulation hardness removal and softening enters the first-effect heater 6, which can reduce the occurrence of scaling in the first-effect heater 6.

[0039] The gas outlet end of the first-effect separator 7 is connected to the side air inlet pipe of the second-effect heater 8. The secondary steam generated after flash evaporation in the first-effect separator 7 can enter the second-effect heater 8 through this pipeline, providing the required heat source for the heating and evaporation work of the second-effect heater 8, thereby reducing the operation and maintenance costs.

[0040] The top port of the second-effect heater 8 is connected to the feed end pipeline of the second-effect separator 9, and the wastewater heated by the second-effect heater 8 can enter the second-effect separator 9 for flash evaporation. The side air outlet of the second-effect heater 8 is connected to the condenser 4 by a pipeline, so that the steam generated at the top of the second-effect heater 8 can enter the condenser 4 from the side air outlet for condensation, and the condensed water is generated for reuse. A second-effect forced circulation pump 11 is arranged on the pipeline connecting the liquid outlet of the crystallization granulation fluidized bed 3 and the bottom port of the second-effect heater 8. The second-effect forced circulation pump 11 can input part of the wastewater flowing out of the liquid outlet of the crystallization granulation fluidized bed 3 into the second-effect heater 8 for heating and evaporation. The specific output and working mode can be determined according to actual conditions.

[0041] The liquid outlet of the second effect separator 9 is respectively connected to the bottom port of the second effect heater 8 and the pipeline of the external dehydration and drying system, and the gas outlet of the second effect separator 9 is connected to the condenser 4 by a pipeline. A part of the high-temperature brine remaining at the bottom of the second effect separator 9 after flash evaporation can flow back to the second effect heater 8 for circulation treatment, and mix with the wastewater entering the crystallization granulation fluidized bed 3 to increase the temperature of the wastewater entering the second effect heater 8 and improve the heat utilization efficiency. The other part can be input into the external dehydration and drying system for dehydration and drying to generate product salt for collection, and the secondary steam accumulated on the top of the second effect separator 9 after flash evaporation can enter the condenser 4 from the gas outlet to condense and generate condensed water for reuse. At the same time, the pipeline connecting the liquid outlet of the second effect separator 9 and the bottom port of the second effect heater 8 passes through the second effect forced circulation pump 11 to realize the control of the circulation.

[0042] The method for using the processing device comprises the following steps:

[0043] The first step: adding seeds into the seed fluidizing tank 1, and then sending fluidizing water to the bottom of the seed fluidizing tank 1 to fluidize the seeds in the seed fluidizing tank 1, starting the seed adding pump 12, and the seed adding pump 12 adds a certain amount of seeds in the seed fluidizing tank 1 into the crystallization granulation fluidized bed 3 for crystallization granulation. After the seed adding is completed, the seed adding pump 12 is closed.

[0044] Step 2: Start the first-effect forced circulation pump 10 to fill the multi-effect evaporation system with high-hardness and high-salt wastewater and circulate it. When the high-hardness and high-salt wastewater enters the granulation fluidized bed 3, the seed crystals begin to fluidize. Start the reagent dosing pump 13, which adds the alkaline reagent in the reagent storage tank 2 into the crystallization granulation fluidized bed 3 to react with the mixed high-hardness and high-salt wastewater to remove hardness ions. At this time, the hardness removed in the crystallization granulation fluidized bed 3 adheres to the surface of the seed crystals and begins to generate calcium carbonate particles.

[0045] The third step: introduce heat source steam into the first-effect heater 6, and the first-effect heater 6 heats the produced water after the hardness is removed by the crystallization granulation fluidized bed 3. The wastewater heated by the first-effect heater 6 enters the first-effect separator 7 for flash separation. After the flash evaporation of the first-effect separator 7, high-temperature reflux water will be generated at the bottom, which is mixed with the incoming high-hardness and high-salt wastewater on the corresponding pipeline, and forced mixing and pressure increase are performed under the action of the first-effect forced circulation pump 10, which increases the subsequent liquid inlet temperature of the crystallization granulation fluidized bed 3 and ensures the flow rate required for the fluidization of the crystal seeds of the crystallization granulation fluidized bed 3. The mixed high-hardness and high-salt wastewater enters the liquid inlet end of the crystallization granulation fluidized bed 3. The hardness of the high-hardness and high-salt wastewater entering the crystallization granulation fluidized bed 3 can be controlled by adjusting the mixing ratio, that is, adjusting the amount of high-hardness and high-salt wastewater entering according to the flow rate of the reflux water, so that the hardness is less than 1500 mg / L, which can reduce the self-nucleation of calcium carbonate crystals, thereby ensuring that the turbidity of the produced water is low enough, and there is no need to increase the precipitation and dehydration system.

[0046] Step 4: Start the second-effect forced circulation pump 11 and the vacuum pump 5, and use the hot steam generated by the flash evaporation of the first-effect separator 7 to continue heating and evaporating the wastewater concentrated by the first-effect evaporation, so that the internal circulation of the multi-effect evaporation system begins and the gas, condensed water and high salt water are discharged; specifically: under the negative pressure of the vacuum pump 5, the hot steam generated by the flash evaporation of the first-effect separator 7 will enter the second-effect heater 8, providing the required heat source for the operation of the second-effect heater 8, thereby reducing the operating cost;

[0047] Under the action of the second-effect forced circulation pump 11, part of the wastewater generated by the crystallization granulation fluidized bed 3 can also enter the second-effect heater 8 for heating. The specific amount of wastewater entering can be determined according to the actual situation, and can be regulated by setting a valve structure such as a regulating valve on the corresponding pipeline. After the wastewater enters the second-effect heater 8 and is heated, it immediately enters the second-effect separator 9 for flash concentration. The top of the second-effect separator 9 will produce secondary steam with a higher temperature, and high-temperature brine will remain at the bottom. Part of the high-temperature brine generated at the bottom of the second-effect separator 9 will flow back to the second-effect heater 8 for circulation treatment, and can be mixed with the wastewater entering from the crystallization granulation fluidized bed 3 to increase the temperature of the wastewater entering the second-effect heater 8 and improve the heat utilization efficiency. The other part can be input into the external dehydration and drying system for dehydration and drying to generate product salt for collection. The specific selection and control of the split flow rate needs to be determined according to the actual situation. The steam accumulated on the top of the second-effect separator 9 can enter the condenser 4 from the gas outlet to be condensed, and the condensed water can be recycled. The steam generated by the second-effect heater 8 can also enter the condenser 4 from the side gas outlet to be condensed, and the condensed water can be recycled.

[0048] The fifth step is to shut down the processing device after it has worked for a certain period of time, and then clean the crystallization granulation fluidized bed 3 to discharge the mature calcium carbonate particles, and then add new crystal seeds to enter a new processing flow.

[0049] Due to rising film evaporation, the flow path of its wastewater is from bottom to top, and a very small amount of calcium carbonate particles that are not adsorbed on the seed crystals may stay and adhere to the heat exchange surfaces of the first effect heater 6 and the second effect heater 8 due to their own gravity, so that scaling may occur in the first effect heater 6 and the second effect heater 8. In order to avoid the occurrence of such a phenomenon as much as possible, embodiment 2 is proposed.

[0050] Example 2: Please refer to Figure 2 The present embodiment provides a treatment device for high-hardness and high-salt wastewater, comprising a seed fluidizing tank 1, a reagent storage tank 2 and a crystallization granulation fluidized bed 3, wherein the seed fluidizing tank 1 is filled with required seeds, the reagent storage tank 2 is filled with required alkaline reagents, the feed end of the crystallization granulation fluidized bed 3 is connected with a pipeline of the seed fluidizing tank 1, a seed dosing pump 12 is arranged on the pipeline connecting the feed end of the crystallization granulation fluidized bed 3 with the discharge end of the seed fluidizing tank 1, the seed dosing pump 12 can pump the seeds in the seed fluidizing tank 1 into the crystallization granulation fluidized bed 3, the drug feed end of the crystallization granulation fluidized bed 3 is connected with a pipeline of the reagent storage tank 2, a reagent dosing pump 13 is arranged on the pipeline connecting the drug feed end of the crystallization granulation fluidized bed 3 with the discharge end of the reagent storage tank 2, the reagent dosing pump 13 can pump the reagent in the reagent storage tank 2 into the crystallization granulation fluidized bed 3.

[0051] The treatment device also includes a multiple-effect evaporation system, the liquid inlet of the multiple-effect evaporation system is connected to the liquid outlet pipe of the crystallization granulation fluidized bed 3, the liquid return of the multiple-effect evaporation system is connected to the liquid inlet pipe of the crystallization granulation fluidized bed 3, the gas outlet pipe of the multiple-effect evaporation system is connected to a condenser 4, and the pipe on the condenser 4 is connected to a vacuum pump 5; the liquid return of the multiple-effect evaporation system is also externally connected to high-hardness and high-salt wastewater, and the high-hardness and high-salt wastewater can be mixed with the return liquid flowing out from the liquid return of the multiple-effect evaporation system and then enter the liquid inlet of the crystallization granulation fluidized bed 3.

[0052] In this embodiment, the multi-effect evaporation system is a falling film evaporation, and the multi-effect evaporation system includes a first-effect heater 6, a first-effect separator 7, a second-effect heater 8 and a second-effect separator 9. The liquid outlet of the crystallization granulation fluidized bed 3 is connected to the top port pipeline of the first-effect heater 6, so that the wastewater discharged from the liquid outlet of the crystallization granulation fluidized bed 3 can enter the first-effect heater 6 for heating and evaporation. At the same time, this layout makes the flow path of the wastewater in the first-effect heater 6 from top to bottom, which is the same as the movement direction of the calcium carbonate particles under the action of gravity, so that the calcium carbonate particles can be easily discharged from the first-effect heater 6 to avoid scaling of the first-effect heater 6 as much as possible.

[0053] The bottom port of the first-effect heater 6 is connected to the liquid inlet pipe of the crystallization granulation fluidized bed 3, and the side port of the first-effect heater 6 is connected to the feed pipe of the first-effect separator 7, so that part of the wastewater after hardness removal by the first-effect heater 6 can enter the first-effect separator 7 for flash evaporation, and the other part can flow back to the crystallization granulation fluidized bed 3 for circulation. A first-effect forced circulation pump 10 is arranged on the pipeline connecting the bottom port of the first-effect heater 6 and the liquid inlet end of the crystallization granulation fluidized bed 3. The pipeline connecting the high-hardness and high-salt wastewater and the liquid inlet end of the crystallization granulation fluidized bed 3 passes through the first-effect forced circulation pump 10. The wastewater heated by the first-effect heater 6 has a high temperature. The high-hardness and high-salt wastewater can be mixed with the reflux water with a high temperature, so as to increase the water inlet temperature of the high-hardness and high-salt wastewater entering the crystallization granulation fluidized bed 3, so as to reduce the solubility of calcium carbonate and the supersaturation required for crystallization, so as to reduce the subsequent dosage of the reagent and reduce the operating cost. At the same time, the self-nucleation of calcium carbonate crystals can be reduced, so that calcium carbonate grows on the crystal seeds, and the low turbidity of the hard water is ensured, and there is no need to set up a sedimentation and sludge dehydration system. In addition, after the high-hardness and high-salt wastewater is mixed with the reflux water, the inlet and outlet water flow of the crystallization granulation fluidized bed 3 can be increased, avoiding the situation that the tower diameter is too small and the tower wall is easy to scale when the flow rate is small. The water softened by crystallization and granulation enters the first-effect heater 6, which can reduce the scaling phenomenon in the first-effect heater 6. The side air inlet pipe of the first-effect heater 6 is connected with heat source steam, which provides the required heat source for the heating and evaporation work of the first-effect heater 6.

[0054] The liquid outlet end of the first-effect separator 7 is respectively connected to the liquid inlet end of the crystallization granulation fluidized bed 3 and the top port pipeline of the second-effect heater 8. After flash evaporation in the first-effect separator 7, part of the wastewater with high temperature will flow back to the crystallization granulation fluidized bed 3, and the other part will enter the second-effect heater 8 for secondary heating and evaporation. The water inlet form of the second-effect heater 8 is arranged in this way, so that the flow path of the wastewater in the second-effect heater 8 can be from top to bottom, which is the same as the movement direction of the calcium carbonate particles under the action of gravity, so that the calcium carbonate particles can be easily discharged from the second-effect heater 8 to avoid scaling of the second-effect heater 8 as much as possible. At the same time, the temperature of the wastewater entering the second-effect heater 8 from the first-effect separator 7 is high, so that the second-effect heater 8 has a higher water inlet temperature, which can improve the heat utilization efficiency. The pipeline connecting the liquid outlet of the first-effect separator 7 and the liquid inlet of the crystallization granulation fluidized bed 3 also passes through the first-effect forced circulation pump 10, and this part of the refluxed wastewater also plays a role in increasing the water inlet temperature and water inlet flow rate of the crystallization granulation fluidized bed 3. The gas outlet of the first-effect separator 7 is connected to the side gas inlet pipeline of the second-effect heater 8, and the hot steam generated after flash evaporation of the first-effect separator 7 can enter the second-effect heater 8 through this pipeline, providing the required heat source for the heating and evaporation work of the second-effect heater 8, so as to reduce the operation and maintenance cost.

[0055] The bottom port of the second-effect heater 8 is connected to the top port pipeline of the second-effect heater 8 to realize the circulation of wastewater, and the side port of the second-effect heater 8 is connected to the feed end pipeline of the second-effect separator 9 so that the wastewater heated and evaporated by the second-effect heater 8 can enter the second-effect separator 9 for flash concentration.

[0056] The liquid outlet end of the second-effect separator 9 is respectively connected to the top port of the second-effect heater 8 and the pipeline of the external dehydration and drying system. A second-effect forced circulation pump 11 is arranged on the pipeline connecting the liquid outlet end of the first-effect separator 7 and the top port of the second-effect heater 8. The pipeline connecting the bottom port of the second-effect heater 8 and the top port of the second-effect heater 8 and the pipeline connecting the liquid outlet end of the second-effect separator 9 and the top port of the second-effect heater 8 are all passed through the second-effect forced circulation pump 11. Through the above-mentioned arrangement, a part of the high-temperature brine remaining at the bottom of the second-effect separator 9 after flash evaporation can flow back to the second-effect heater 8 for circulation treatment, and can be mixed with the wastewater discharged from the second-effect heater 8 and the wastewater discharged from the first-effect separator 7 to increase the water inlet amount and water inlet temperature of the wastewater entering the second-effect heater 8 and improve the heat utilization efficiency. The other part can be input into the external dehydration and drying system for dehydration and drying to generate product salt for collection. The gas outlet end of the second-effect separator 9 is connected to the condenser 4 through a pipeline, so that the secondary steam accumulated on the top of the second-effect separator 9 after flash evaporation can enter the condenser 4 from the gas outlet end for condensation to generate condensed water for reuse.

[0057] The method for using the processing device comprises the following steps:

[0058] The first step: adding seeds into the seed fluidizing tank 1, and then sending fluidizing water to the bottom of the seed fluidizing tank 1 to fluidize the seeds in the seed fluidizing tank 1, starting the seed adding pump 12, and the seed adding pump 12 adds a certain amount of seeds in the seed fluidizing tank 1 into the crystallization granulation fluidized bed 3 for crystallization granulation. After the seed adding is completed, the seed adding pump 12 is closed.

[0059] Step 2: Start the first-effect forced circulation pump 10 to fill the multi-effect evaporation system with high-hardness and high-salt wastewater and circulate it. When the high-hardness and high-salt wastewater enters the granulation fluidized bed 3, the seed crystals begin to fluidize. Start the reagent dosing pump 13, which adds the alkaline reagent in the reagent storage tank 2 into the crystallization granulation fluidized bed 3 to react with the mixed high-hardness and high-salt wastewater to remove hardness ions. At this time, the hardness removed in the crystallization granulation fluidized bed 3 adheres to the surface of the seed crystals and begins to generate calcium carbonate particles.

[0060] The third step: introduce heat source steam into the first-effect heater 6, and the first-effect heater 6 heats the produced water after the hardness is removed by the crystallization granulation fluidized bed 3. The wastewater heated by the first-effect heater 6 enters the first-effect separator 7 for flash separation. After the flash evaporation of the first-effect separator 7, high-temperature reflux water will be generated at the bottom, which is mixed with the incoming high-hardness and high-salt wastewater on the corresponding pipeline, and forced mixing and pressure increase are performed under the action of the first-effect forced circulation pump 10, which increases the subsequent liquid inlet temperature of the crystallization granulation fluidized bed 3 and ensures the flow rate required for the fluidization of the crystal seeds of the crystallization granulation fluidized bed 3. The mixed high-hardness and high-salt wastewater enters the liquid inlet end of the crystallization granulation fluidized bed 3. The hardness of the high-hardness and high-salt wastewater entering the crystallization granulation fluidized bed 3 can be controlled by adjusting the mixing ratio, that is, adjusting the amount of high-hardness and high-salt wastewater entering according to the flow rate of the reflux water, so that the hardness is less than 1500 mg / L, which can reduce the self-nucleation of calcium carbonate crystals, thereby ensuring that the turbidity of the produced water is low enough, and there is no need to increase the precipitation and dehydration system.

[0061] Step 4: Start the second-effect forced circulation pump 11 and the vacuum pump 5, and use the hot steam generated by the flash evaporation of the first-effect separator 7 to continue heating and evaporating the wastewater concentrated by the first-effect evaporation, so that the internal circulation of the multi-effect evaporation system begins and the gas, condensed water and high salt water are discharged; specifically: under the negative pressure of the vacuum pump 5, the hot steam generated by the flash evaporation of the first-effect separator 7 will enter the second-effect heater 8, providing the required heat source for the operation of the second-effect heater 8, thereby reducing the operating cost;

[0062] Under the action of the second-effect forced circulation pump 11, a part of the wastewater generated by the first-effect separator 3 can also enter the second-effect heater 8 for heating. The specific amount of wastewater entering can be determined according to the actual situation, and can be regulated by setting a valve structure such as a regulating valve on the corresponding pipeline. After the wastewater enters the second-effect heater 8 and is heated, it immediately enters the second-effect separator 9 for flash concentration. The top of the second-effect separator 9 will produce secondary steam with a higher temperature, and high-temperature brine will remain at the bottom. A part of the high-temperature brine generated at the bottom of the second-effect separator 9 will flow back to the second-effect heater 8 for circulation treatment, and can be mixed with the wastewater entering from the bottom 3 of the first-effect separator to increase the temperature of the wastewater entering the second-effect heater 8 and improve the heat utilization efficiency. The other part can be input into the external dehydration and drying system for dehydration and drying to generate product salt for collection. The specific flow rate selection control needs to be determined according to the actual situation. The steam accumulated at the top of the second-effect separator 9 can enter the condenser 4 from the gas outlet to condense and generate condensed water for reuse.

[0063] The fifth step is to shut down the processing device after it has worked for a certain period of time, and then clean the crystallization granulation fluidized bed 3 to discharge the mature calcium carbonate particles, and then add new crystal seeds to enter a new processing flow.

[0064] The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A device for treating high-hardness and high-salt wastewater, comprising a seed fluidized bed tank (1), a reagent storage tank (2) and a crystallization granulation fluidized bed (3), wherein the crystallization granulation fluidized bed (3) is connected to the seed fluidized bed tank (1) and the reagent storage tank (2) by pipelines, and characterized in that: The treatment device also includes a multiple-effect evaporation system, wherein the liquid inlet of the multiple-effect evaporation system is connected to the liquid outlet pipe of the crystallization granulation fluidized bed (3), the liquid return of the multiple-effect evaporation system is connected to the liquid inlet pipe of the crystallization granulation fluidized bed (3), the gas outlet pipe of the multiple-effect evaporation system is connected to a condenser (4), and the pipe of the condenser (4) is connected to a vacuum pump (5); the liquid return of the multiple-effect evaporation system is also externally connected to high-hardness and high-salt wastewater, and the high-hardness and high-salt wastewater can be mixed with the liquid return flowing out of the liquid return of the multiple-effect evaporation system and then enter the liquid inlet of the crystallization granulation fluidized bed (3).

2. The device for treating high-hardness and high-salt wastewater according to claim 1, characterized in that: The multiple-effect evaporation system comprises a first-effect heater (6), a first-effect separator (7), a second-effect heater (8) and a second-effect separator (9), and the multiple-effect evaporation system is used for performing rising film evaporation or falling film evaporation.

3. A device for treating high-hardness and high-salt wastewater according to claim 2, characterized in that: The liquid outlet of the crystallization granulation fluidized bed (3) is connected to the bottom port of the first effect heater (6) and the bottom port of the second effect heater (8) through pipelines, respectively; the top port of the first effect heater (6) is connected to the feed end pipeline of the first effect separator (7); the upper pipeline of the side air inlet of the first effect heater (6) is connected to heat source steam; the liquid outlet of the first effect separator (7) is connected to the liquid inlet pipeline of the crystallization granulation fluidized bed (3); the air outlet of the first effect separator (7) is connected to the side air inlet pipeline of the second effect heater (8); the top port of the second effect heater (8) is connected to the feed end pipeline of the second effect separator (9); the side air outlet of the second effect heater (8) is connected to the condenser (4) through a pipeline; the liquid outlet of the second effect separator (9) is connected to the bottom port of the second effect heater (8) and the external dehydration and drying system pipeline, respectively; and the air outlet of the second effect separator (9) is connected to the condenser (4) through a pipeline.

4. The device for treating high-hardness and high-salt wastewater according to claim 3, characterized in that: A first-effect forced circulation pump (10) is provided on the pipeline connecting the liquid outlet end of the first-effect separator (7) and the liquid inlet end of the crystallization granulation fluidized bed (3), and the pipeline connecting the high-hardness and high-salt wastewater and the liquid inlet end of the crystallization granulation fluidized bed (3) passes through the first-effect forced circulation pump (10).

5. The device for treating high-hardness and high-salt wastewater according to claim 3, characterized in that: A second-effect forced circulation pump (11) is provided on the pipeline connecting the liquid outlet end of the crystallization granulation fluidized bed (3) and the bottom port of the second-effect heater (8), and the pipeline connecting the liquid outlet end of the second-effect separator (9) and the bottom port of the second-effect heater (8) passes through the second-effect forced circulation pump (11).

6. The device for treating high-hardness and high-salt wastewater according to claim 2, characterized in that: The liquid outlet of the crystallization granulation fluidized bed (3) is connected to the top port pipeline of the first-effect heater (6), the bottom port of the first-effect heater (6) is connected to the liquid inlet pipeline of the crystallization granulation fluidized bed (3), the side port of the first-effect heater (6) is connected to the feed end pipeline of the first-effect separator (7), the side air inlet pipeline of the first-effect heater (6) is connected to the heat source steam, and the liquid outlet of the first-effect separator (7) is respectively connected to the liquid inlet end of the crystallization granulation fluidized bed (3) and the top port pipeline of the second-effect heater (8). The first-effect separator (7) is connected to the side air inlet pipe of the second-effect heater (8), the bottom port of the second-effect heater (8) is connected to the top port pipe of the second-effect heater (8), the side port of the second-effect heater (8) is connected to the feed end pipe of the second-effect separator (9), the liquid outlet end of the second-effect separator (9) is respectively connected to the top port of the second-effect heater (8) and the external dehydration and drying system pipe, and the gas outlet end of the second-effect separator (9) is connected to the condenser (4) through a pipe.

7. A device for treating high-hardness and high-salt wastewater according to claim 6, characterized in that: A first-effect forced circulation pump (10) is provided on the pipeline connecting the bottom port of the first-effect heater (6) and the liquid inlet end of the crystallization granulation fluidized bed (3), and the pipeline connecting the liquid outlet end of the first-effect separator (7) and the liquid inlet end of the crystallization granulation fluidized bed (3) and the pipeline connecting the high-hardness and high-salt wastewater and the liquid inlet end of the crystallization granulation fluidized bed (3) all pass through the first-effect forced circulation pump (10).

8. The device for treating high-hardness and high-salt wastewater according to claim 6, characterized in that: A second-effect forced circulation pump (11) is arranged on the pipeline connecting the liquid outlet end of the first-effect separator (7) and the top port of the second-effect heater (8), and the pipeline connecting the bottom port of the second-effect heater (8) and the top port of the second-effect heater (8) and the pipeline connecting the liquid outlet end of the second-effect separator (9) and the top port of the second-effect heater (8) both pass through the second-effect forced circulation pump (11).

9. The device for treating high-hardness and high-salt wastewater according to claim 1, characterized in that: A seed dosing pump (12) is provided on the pipeline connecting the feed end of the crystallization granulation fluidized bed (3) and the seed fluidization tank (1), and a drug dosing pump (13) is provided on the pipeline connecting the drug feed end of the crystallization granulation fluidized bed (3) and the drug storage tank (2).

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