Softened water preparation device with high hardness removal rate

Abstract

The utility model relates to a softened water preparation device, in particular to a softened water preparation device with high hardness removal rate. The utility model relates to a softened water preparation device with high hardness removal rate, which comprises a water inlet pipe, a reaction chamber I, a settling chamber I, a settling chamber II, a reaction chamber II, a settling chamber III, a settling chamber IV, an immersed UF reaction tank, an adjusting chamber, an ion exchange chamber and a water outlet pipe which are sequentially arranged, a sodium carbonate solution adding opening is formed between the settling chamber II and the reaction chamber II.

Description

Technical Field

[0001] The utility model relates to a softened water preparation device, in particular to a softened water preparation device with a high hardness removal rate. Background Art

[0002] Industrial water has certain requirements for hardness index, especially boiler water, so it is particularly important to soften and desalinate industrial water. Hardness salts include Ca 2+ Mg 2+ 、Fe 2+ 、Mn 2+ 、Fe 3+ 、Al 3+ Such metal cations that easily form insoluble salts.

[0003] At present, there are mainly the following methods for water softening: 1. Chemical softening method (precipitation softening method), based on the solubility product principle, adding certain chemicals to convert calcium and magnesium ions in water into insoluble compounds to precipitate them; 2. Ion exchange softening method, based on the ion exchange principle, using the cations of certain ion exchangers, such as Na + 、H + Exchange reaction with calcium and magnesium ions in water to achieve the purpose of softening; 3. Electrodialysis method, based on the principle of electrodialysis, utilizes the selective permeability of ion exchange membrane. Under the action of external DC electric field, through the migration of ions, it achieves the purpose of softening while carrying out local desalination of water. Summary of the Invention

[0004] The utility model hopes to provide a softened water preparation device with a high hardness removal rate. The specific scheme is as follows:

[0005] A softened water production device with a high hardness removal rate comprises a water inlet pipe, a reaction chamber 1, a sedimentation chamber 1, a sedimentation chamber 2, a reaction chamber 2, a sedimentation chamber 3, a sedimentation chamber 4, an immersion UF reaction tank, a regulating chamber, an ion exchange chamber and a water outlet pipe, the feed pipe being provided with a lime emulsion addition port, and a sodium carbonate solution addition port being provided between the sedimentation chamber 2 and the reaction chamber 2.

[0006] The bottoms of the reaction chamber 1, sedimentation chamber 1, sedimentation chamber 2, reaction chamber 2, sedimentation chamber 3, sedimentation chamber 4 and the submerged UF reaction tank are all connected to a sludge collection hopper, and the sludge collection hopper is connected to a sludge discharge pipe.

[0007] A guide wall is provided between the reaction chamber 1, the precipitation chamber 1, the precipitation chamber 2, the reaction chamber 2, the precipitation chamber 3 and the precipitation chamber 4.

[0008] The utility model provides a process equipment which organically combines three technologies: reagent softening, submerged ultrafiltration membrane technology, and ion exchange technology. Reagent softening is mainly used to remove the hardness and alkalinity in water; the submerged ultrafiltration membrane is mainly used for mud-water separation to improve the influent water quality of the ion exchanger; the ion exchanger is mainly used for high-precision hard removal to further remove the hardness in water, so as to obtain high-quality softened water. The characteristics of the utility model are as follows: 1. Strong universality, suitable for water with high hardness and high alkalinity, and good softening effect; 2. Lower operating cost and strong adaptability to changes in water quality and water volume; 3. Simple equipment, small floor area, and convenient operation and maintenance. Brief Description of the Drawings

[0009] Figure 1 It is a schematic structural diagram of a softened water production device with a high hard removal rate of the utility model;

[0010] Among them, the labels are: 1. Water inlet pipe; 2. First reaction chamber; 3. First sedimentation chamber; 4. Second sedimentation chamber; 5. Second reaction chamber; 6. Third sedimentation chamber; 7. Fourth sedimentation chamber; 8. Submerged UF reaction tank; 9. Regulation chamber; 10. Ion exchange chamber; 11. Water outlet pipe; 12. Sludge discharge pipe; 13. Flow guiding wall. Detailed Embodiment

[0011] The following is further described in conjunction with Figure 1 for further illustration:

[0012] A softened water production device with a high hard removal rate includes a water inlet pipe 1, a first reaction chamber 2, a first sedimentation chamber 3, a second sedimentation chamber 4, a second reaction chamber 5, a third sedimentation chamber 6, a fourth sedimentation chamber 7, a submerged UF reaction tank 8, a regulation chamber 9, an ion exchange chamber 10, and a water outlet pipe 11 arranged in sequence. A lime emulsion dosing port is provided on the feed pipe, and a sodium carbonate solution dosing port is provided between the second sedimentation chamber 4 and the second reaction chamber 5.

[0013] The bottoms of the first reaction chamber 2, the first sedimentation chamber 3, the second sedimentation chamber 4, the second reaction chamber 5, the third sedimentation chamber 6, the fourth sedimentation chamber 7, and the submerged UF reaction tank 8 are all connected with sludge collection hoppers, and the sludge collection hoppers are connected with the sludge discharge pipe 12.

[0014] Flow guiding walls 13 are provided between the first reaction chamber 2, the first sedimentation chamber 3, the second sedimentation chamber 4, the second reaction chamber 5, the third sedimentation chamber 6, and the fourth sedimentation chamber 7.

[0015] Technical Principle:

[0016] 1. Reagent Softening

[0017] By adding lime or making lime emulsion with a certain concentration, the HCO-3 ions in water are converted into CO2-3 ions, and the lime provides the required OH -ions, convert HCO-3 and produce excess CO2-3 ions, which react with Ca ions in the raw water to form CaCO3 precipitate and precipitate out. Ca(OH)2 can react with CO2 to form CaCO3 precipitate and react with MgCO3 to form Mg(OH)2 precipitate. In addition, Ca(OH)2 can also remove some iron and silicon compounds in the water, and react with the magnesium hardness of non-carbonate in the water to form Mg(OH)2 precipitate, but at the same time, it produces an equal amount of calcium hardness of non-carbonate, which can be used in combination with sodium carbonate solution. Sodium carbonate solution is used to reduce the non-carbonate hardness of water, convert CaSO4, CaCl2, MgSO4, MgCl2 into CaCO3 and Mg(OH)2 precipitates, and is suitable for water with hardness greater than alkalinity. After lime treatment, the residual carbonate hardness of water can be reduced to 0.25 - 0.50 mmol / L, the residual alkalinity is about 0.8 - 1.2 mmol / L, about 30% - 35% of silicon compounds can be removed, 25% of organic matter can be removed, and the iron residue is about 0.1 mg / L. 2+ Ca(OH)2 can react with CO2 to form CaCO3 precipitate and react with MgCO3 to form Mg(OH)2 precipitate. In addition, Ca(OH)2 can also remove some iron and silicon compounds in the water, and react with the magnesium hardness of non-carbonate in the water to form Mg(OH)2 precipitate, but at the same time, it produces an equal amount of calcium hardness of non-carbonate, which can be used in combination with sodium carbonate solution. Sodium carbonate solution is used to reduce the non-carbonate hardness of water, convert CaSO4, CaCl2, MgSO4, MgCl2 into CaCO3 and Mg(OH)2 precipitates, and is suitable for water with hardness greater than alkalinity. After lime treatment, the residual carbonate hardness of water can be reduced to 0.25 - 0.50 mmol / L, the residual alkalinity is about 0.8 - 1.2 mmol / L, about 30% - 35% of silicon compounds can be removed, 25% of organic matter can be removed, and the iron residue is about 0.1 mg / L.

[0018] 2. Submerged ultrafiltration membrane (submerged UF reaction tank 8) filtration

[0019] Ultrafiltration is used to intercept particles of colloidal size in water, while water and low molecular weight solutes are allowed to pass through the membrane. The average pore size of the ultrafiltration membrane is between that of the reverse osmosis membrane and the microfiltration membrane. This patent uses a submerged ultrafiltration membrane to further filter the clarified water after chemical softening, remove suspended solids in the water, and improve the water quality of the influent for the ion exchange resin process.

[0020] 3. Ion exchange method

[0021] The resin active groups are divided into strong acid, strong base, weak acid, and weak base. The pH value of water will inevitably affect its exchange capacity. The active groups of strong acid and strong base resins have strong ionization ability, and their exchange capacity is basically independent of the pH value. Currently, the commonly used methods include Na ion exchange method, H ion exchange method, and H-Na ion exchange method, etc. The Na ion exchange is the simplest softening method. The advantage of this method is that no acidic water is produced during the treatment process, the regenerant is salt, and the anti-corrosion facilities for equipment and pipelines are simple. For the softening reaction of strongly acidic H-type ion exchange resin, the carbonate hardness in the raw water forms carbonic acid during the exchange process, so in addition to softening, it can also remove alkalinity. During the exchange process of non-carbonate hardness, in addition to softening, the corresponding acid is generated. Since the effluent of H ion exchange is often acidic, it is generally always used in combination with Na ion exchange or combined with other measures. This patent uses the H-Na ion exchange method.

[0022] Ion exchange units utilize a fixed bed, the most basic type of ion exchange unit. Ion exchange resin or sulfonated coal is loaded into the ion exchanger. This patent utilizes a countercurrent regeneration fixed bed, meaning the raw water and regeneration fluid flow in opposite directions. Countercurrent regeneration operates with the regeneration fluid flowing upward and the water flowing downward. Air-top pressure or water-top pressure methods can be employed. This patent utilizes the air-top pressure method, injecting compressed air at a pressure of approximately 30-50 kPa into the top of the exchanger before regeneration. This ensures uniform stratification at normal regeneration flow rates. Unlike conventional co-current regeneration equipment, this method incorporates an intermediate drain device installed on the surface of the resin bed to drain the upward-flowing regeneration fluid and rinse water. The pressure from the compressed air above prevents stratification. Furthermore, a layer of resin or an inert resin (lighter than resin but slightly heavier than water) approximately 15 cm thick is placed above the intermediate drain device. This layer, known as a grease layer, ensures a more even and gradual escape of compressed air from the intermediate drain device and also provides a filtering effect.

[0023] Operation process:

[0024] Step 1: Raw water enters the reaction equipment, first contacts and mixes with the lime emulsion in the lime emulsion feeding port, and then enters the reaction chamber 2 through the narrow flow channel in the guide wall 13. The main function of the reaction chamber 2 is to convert the HCO-3 ions in the water into CO2-3 ions, converting the HCO-3 and generating excess CO2-3 ions, so that they react with the Ca in the raw water. 2+ Ions generate CaCO3 precipitation; Ca(OH)2 can react with CO2 to generate CaCO3 precipitation, and with MgCO3 to generate Mg(OH)2 precipitation; Ca(OH)2 can also remove some iron and silicon compounds in the water, and can also react with non-carbonate magnesium hardness in the water to generate Mg(OH)2 precipitation. The generated precipitated sludge is deposited into the sludge collection hopper below the reaction chamber 2 and discharged through the sludge discharge pipe 12

[0025] Step 2: The effluent from reaction chamber 2 flows through the narrow flow channel within the guide wall 13 and enters the sedimentation chamber 3. The function of the sedimentation chamber 3 is to perform the first sedimentation of the effluent from reaction chamber 2, and the sludge is settled into the sludge collection hopper below the sedimentation chamber 3 and discharged through the sludge discharge pipe 12.

[0026] Step 3: The effluent from Sedimentation Chamber 1 3 flows through the narrow channel in the guide wall 13 and enters Sedimentation Chamber 2 4 . Sedimentation Chamber 2 4 is used to perform a second sedimentation on the effluent from Sedimentation Chamber 1 3 , depositing the sludge into the sludge collection hopper below Sedimentation Chamber 2 4 and discharging it through the sludge discharge pipe 12 .

[0027] Step 4: Before the effluent from the second sedimentation chamber 4 enters the reactor 2, it will come into contact with the sodium carbonate solution added through the sodium carbonate solution dosing port. After mixing, it enters the second reaction chamber 5 through the narrow flow channels in the diversion wall 13 for precipitation reaction. The main function of the second reaction chamber 5 is to remove the non-carbonate hardness in the water, and the remaining hardness of the softened water can be reduced to 0.15 - 0.2 mmol / L.

[0028] Step 5: The effluent from the second reaction chamber 5 enters the third sedimentation chamber 6 through the narrow flow channels in the diversion wall 13 respectively. The function of the third sedimentation chamber 6 is to conduct the first sedimentation on the effluent from the second reaction chamber 5, precipitate the sludge to the sludge collection hopper below the third sedimentation chamber 6, and discharge the sludge through the sludge discharge pipe 12.

[0029] Step 6: The effluent from the third sedimentation chamber 6 enters the fourth sedimentation chamber 7 through the narrow flow channels in the diversion wall 13 respectively. The function of the fourth sedimentation chamber 7 is to conduct the second sedimentation on the effluent from the third sedimentation chamber 6, precipitate the sludge to the sludge collection hopper below the fourth sedimentation chamber 7, and discharge the sludge through the sludge discharge pipe 12.

[0030] Step 7: The effluent from the fourth sedimentation chamber 7 enters the submerged ultrafiltration reaction tank (i.e., the submerged UF reaction tank 8) through the water outlet. In the reaction tank, the final separation of mud and water is carried out through the membrane device. The effluent from the membrane tank enters the regulation chamber 9, and the mud is discharged to the sludge discharge pipe 12 through the sludge collection hopper at the bottom of the membrane tank for sludge discharge.

[0031] Step 9: The water in the regulation chamber 9 enters the ion exchange chamber 10 for final hardness removal. The ion exchanger for softening is a steel tank that can withstand a pressure of 0.4 - 0.6 MPa. Its internal structure is divided into three parts: the upper water distribution pipe system, the resin layer, and the lower water distribution pipe system, and its structure is similar to that of a pressure filter. The height of the resin layer is generally 1.5 - 2.0 m. There is enough space at the upper part to ensure the expansion of the resin layer during backwashing. The effluent can be discharged to the product water tank or the degasser for further removal of dissolved gases in the water.

[0032] Step 10: In the operation of the fixed bed, the exchange process is the softening process, while the three steps of backwashing, regeneration, and cleaning belong to the regeneration process. The steps of countercurrent regeneration operation are as follows: small backwashing. Introduce backwash water from the middle drainage device to wash the resin pressing layer, with a flow rate of about 5 - 10 m / h and a duration of 10 - 15 min; drain water. Drain the water in the upper part of the middle drainage device; top pressure. Introduce compressed air from the top of the exchanger to maintain the air pressure at 30 - 50 kPa; introduce the regeneration liquid. Introduce the regeneration liquid from the bottom of the exchanger, with an upward flow rate of about 5 m / h; reverse cleaning. Use softened water for countercurrent cleaning with a flow rate of 5 - 7 m / h until the discharged water meets the requirements; normal washing. Conduct normal washing until the effluent quality meets the operation control standard, and then it can be transferred to operation. The normal washing flow rate is 10 - 15 m / h.

[0033] Step 11: After the countercurrent regeneration fixed bed has been operating for several weeks, a major backwash should be carried out to remove dirt and debris in the resin bed. When regenerating for the first time after the major backwash, the consumption of the regenerant should be appropriately increased. Countercurrent regeneration should be carried out with softened water; otherwise, the already regenerated resin at the bottom layer will be consumed again during the cleaning process, resulting in a decline in the quality of the effluent and losing the advantages of countercurrent regeneration.

[0034] Features:

[0035] In the chemical softening of water, lime is the most commonly added chemical. Due to its low price and wide availability, it is very suitable for occasions where the carbonate hardness of the raw water is relatively high, the non-carbonate hardness is relatively low, and deep softening is not required. If the dosage of lime is inappropriate, it will make the effluent quality unstable and bring difficulties to operation and management. Therefore, the actual dosage of lime should be adjusted in production practice. Lime can also be used in combination with the sodium ion exchange method for cases where the carbonate hardness of the raw water is relatively high and deep softening is required. In this case, lime softening can be used as a pretreatment for the sodium ion exchange method.

[0036] Submerged ultrafiltration membrane separation (submerged UF reaction tank 8) is used as a pretreatment for the ion exchange method, realizing the separation of water and suspended solids in the chemically softened precipitate water. Under the separation and filtration of the membrane module, the separation of mud and water is finally achieved. This technology has good treatment effects and great adaptability to changes in water volume and quality. The submerged ultrafiltration membrane module can efficiently achieve solid-liquid separation, greatly removing suspended solids. The SS concentration in the treated water will be lower than 5 mg / L, and the turbidity will be lower than 1 NTU. The separation effect is far better than that of traditional sedimentation tanks. In addition, the submerged ultrafiltration membrane reactor has a strong ability to withstand shock loads and has good adaptability to changes in the water volume and quality of the influent.

[0037] This utility model adopts a countercurrent regeneration fixed bed with an upward flowing regenerant and a downward flowing water stream. During regeneration, the regenerant first contacts the bottom layer resin with a low degree of saturation, and then regenerates the middle and upper layer resins with a higher degree of saturation. In this way, the regenerant is fully utilized, the consumption of the regenerant is significantly reduced (the consumption of the regenerant can be reduced by more than 20%), and it can ensure that the bottom layer resin is fully regenerated. Moreover, the effective concentration of the regenerant in the regenerated waste liquid is significantly reduced, generally not exceeding 1%. During softening, the treated water contacts this bottom layer resin again after sufficient softening for full exchange, thereby improving the effluent quality (the applicable range of the influent water quality is expanded, and for water with a relatively high hardness, the effluent quality can still be guaranteed).

[0038] The above content describes the technical principle, beneficial effects, and features of this invention. It should be noted that the above is only the preferred embodiment of this invention, but it is not limited by the above embodiments. For those skilled in the art of this invention, without departing from the content of this invention, some improvements and optimizations can be made, and these should be regarded as belonging to the protection scope of this invention.

Claims

1. A softened water preparation device with high hardness removal rate, characterized by: The invention comprises a water inlet pipe, a reaction chamber 1, a sedimentation chamber 1, a sedimentation chamber 2, a reaction chamber 2, a sedimentation chamber 3, a sedimentation chamber 4, an immersion UF reaction tank, a regulating chamber, an ion exchange chamber and a water outlet pipe, wherein the water inlet pipe is provided with a lime emulsion addition port, and a sodium carbonate solution addition port is provided between the sedimentation chamber 2 and the reaction chamber 2.

2. The softened water preparation device with high hardness removal rate according to claim 1, characterized in that: The bottoms of the reaction chamber 1, sedimentation chamber 1, sedimentation chamber 2, reaction chamber 2, sedimentation chamber 3, sedimentation chamber 4 and the submerged UF reaction tank are all connected to a sludge collection hopper, and the sludge collection hopper is connected to a sludge discharge pipe.

3. The softened water preparation device with high hardness removal rate according to claim 1, characterized in that: A guide wall is provided between the reaction chamber 1, the precipitation chamber 1, the precipitation chamber 2, the reaction chamber 2, the precipitation chamber 3 and the precipitation chamber 4.

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