A pH-adjustable ion exchange device and pH adjustment method

Abstract

The present invention is a pH adjustable ion exchange device and a pH adjustment method, the structure of which includes a carbon steel rubber lined tank body, and the interior of the tank body is filled with an ion exchange resin bed composed of weak anion exchange resin. The pH adjustment method includes: the system inlet water and the regenerated resin are mixed in the system water inlet pipe and then enter the tank body from the water inlet, and after being fully exchanged by the ion exchange resin bed, they are collected by the system outlet water collector and discharged from the outlet to become the system outlet water, and the failed resin is discharged from the resin discharge pipe. Advantages of the present invention: 1) The degree of ion exchange can be controlled, opening up a new application path for the application scope of ion exchange; 2) When applied to a wastewater reuse system containing acid and alkali, during the process of pH adjustment of the treated water, the salt content in the water is reduced, which can provide more favorable conditions for subsequent recycling treatment, help reduce the operating cost of the overall system, and improve the recovery rate of the system.

Description

Technical Field

[0001] The invention relates to a pH-adjustable ion exchange device and a pH-adjusting method, belonging to the technical field of industrial water treatment. Background Art

[0002] When treating wastewater containing acidity and alkalinity, one of the important links in the treatment process is to make the pH value of the treated water controllable.

[0003] The prior art generally uses the method of directly adding acid and alkali to water to adjust the pH of the treated water. However, although the method of directly adding acid and alkali to water can achieve the purpose of pH adjustment, the salt content in the water also increases with the pH adjustment process. If the treated acid and alkali wastewater needs to be recycled, the increase in salt content will directly lead to increased difficulty in the subsequent recycling and treatment system, increased energy consumption, and decreased treatment recovery rate.

[0004] In view of the above problems, a pH-adjustable ion exchange device and a pH adjustment method are studied to achieve the purpose of controllable adjustment of the pH value while reducing the salt content in the water, providing more favorable water inlet conditions for subsequent recovery and treatment, reducing the operating cost of the overall system, and improving the recovery rate of the system, which is of great positive significance. Summary of the invention

[0005] The present invention provides a pH adjustable ion exchange device and a pH adjustment method, the purpose of which is to overcome the above-mentioned defects of the prior art, using the ion exchange principle, using a pH adjustable ion exchange device and a pH adjustment method. + Ion or OH - The ion exchange resin and water containing acidity and alkalinity are exchanged so that the pH of the treated water can be controlled and adjusted. At the same time, some anions and cations in the water can be removed to reduce the salt content in the water.

[0006] The technical solution of the present invention is as follows: the pH adjustable ion exchange device comprises a carbon steel rubber lined tank body, an ion exchange resin bed composed of weak anion exchange resin is filled in the tank body, a water inlet is arranged on the top of the tank body, the water inlet is located at one end of the outer side of the tank body and connected to the system water inlet pipe, the middle of the system water inlet pipe is connected to the regeneration resin replenishment pipe, the regeneration resin replenishment pipe is provided with a regeneration resin replenishment regulating valve, the upper part of the tank body is provided with a resin height detector installation port, the resin height detector is arranged on the upper part of the tank body through the resin height detector installation port, and is connected to the resin height detector by the resin height detector installation port. The resin height detector probe connected to the meter extends to the inside of the tank body through the resin height detector installation port. A water outlet is arranged at the lower part of the tank body. The water outlet is located at one end of the inner side of the tank body and a system water outlet manifold is arranged. The water outlet is located at one end of the outer side of the tank body and is connected to a water outlet pipe. A system water outlet pH meter is arranged on the water outlet pipe. A resin discharge port is arranged at the bottom of the tank body. The resin discharge port is located at one end of the outer side of the tank body and is connected to a resin discharge pipe. A failed resin discharge regulating valve is arranged on the resin discharge pipe. The regenerated resin replenishment regulating valve, the resin height detector and the system water outlet pH meter are all connected to the control system signal.

[0007] Preferably, the water inlet is located at one end of the inner side of the tank body and is connected to the system water inlet distributor.

[0008] Preferably, the resin height detector installation port is located at one end of the inner side of the tank body and a semi-enclosed resin height detector anti-interference cover is provided, and the resin height detector probe is located inside the resin height detector anti-interference cover 301.

[0009] A pH adjustment method for a pH-adjustable ion exchange device, the method comprising the following steps: during normal operation, system influent water and regenerated resin are mixed in the system inlet pipe and then enter the tank body from the water inlet, and after being fully exchanged by the ion exchange resin bed, they are collected by the system outlet water collector and then discharged from the outlet to become system outlet water, and the failed resin is discharged from the resin discharge pipe.

[0010] Preferably, the regenerated resin replenishment speed is controlled by the opening of the regenerated resin replenishment regulating valve, and the opening of the regenerated resin replenishment regulating valve is jointly controlled by the pH value detected by the system water outlet pH meter and the control target set by the control system, ensuring that the pH value of the system water outlet is always close to the control target set in the control system.

[0011] Preferably, the effluent pH control target is set to 5.5.

[0012] Preferably, the speed of the failed resin discharge is controlled by the opening of the failed resin discharge regulating valve, and the opening of the failed resin discharge regulating valve is controlled by the resin height detected by the resin height detector and the control target set in the control system, ensuring that the resin layer height of the ion exchange resin bed is always close to the control target set in the control system.

[0013] The advantages of the present invention are as follows: 1) the degree of ion exchange can be controlled, opening up a new application path for the application scope of ion exchange; 2) when applied to a wastewater reuse system containing acid and alkali, during the pH adjustment process of the treated water, the salt content in the water is reduced, which can provide more favorable conditions for subsequent recovery and treatment, help reduce the operating cost of the overall system, and improve the recovery rate of the system; specifically, during the ion exchange pH adjustment process, not only can the pH value of the water be adjusted, but also a part of the anions and TOC in the water can be exchanged and removed, and then after subsequent chemical precipitation, the salt content in the water is lower, which is conducive to membrane recovery and treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic structural diagram of the pH adjustable ion exchange device of the present invention.

[0015] In the figure, 1 is the tank body, 101 is the ion exchange resin bed, 2 is the water inlet, 201 is the system water inlet pipe, 202 is the regenerated resin replenishment regulating valve, 203 is the system water inlet water distributor, 3 is the resin height detector installation port, 301 is the resin height detector anti-interference cover, 302 is the resin height detector, 3021 is the resin height detector probe, 4 is the water outlet, 401 is the system water outlet collector, 402 is the system water outlet pH meter, 5 is the resin discharge port, 501 is the failed resin discharge regulating valve, and 6 is the control system. DETAILED DESCRIPTION

[0016] The present invention is further described in detail below with reference to examples and specific implementation modes.

[0017] like Figure 1As shown, the pH adjustable ion exchange device comprises a tank body 1 lined with carbon steel rubber, an ion exchange resin bed 101 composed of weak anion exchange resin is filled inside the tank body 1, a water inlet 2 is arranged on the top of the tank body 1, the water inlet 2 is located at one end of the outer side of the tank body 1 and connected to a system water inlet pipe 201, a regeneration resin replenishing pipe is connected to the middle of the system water inlet pipe 201, a regeneration resin replenishing regulating valve 202 is arranged on the regeneration resin replenishing pipe, a resin height detection meter installation port 3 is arranged on the upper part of the tank body 1, a resin height detection meter 302 is arranged on the upper part of the tank body 1 through the resin height detection meter installation port 3, and a resin height detection meter 302 connected to the resin height detection meter 302 is arranged on the upper part of the tank body 1. The height detection meter probe 3021 extends to the interior of the tank body 1 through the resin height detection meter installation port 3. A water outlet 4 is provided at the lower part of the tank body 1. The water outlet 4 is located at one end of the inner side of the tank body 1 and a system water outlet collector 401 is provided. The water outlet 4 is located at one end of the outer side of the tank body 1 and is connected to a water outlet pipe. A system water outlet pH meter 402 is provided on the water outlet pipe. A resin discharge port 5 is provided at the bottom of the tank body 1. The resin discharge port 5 is located at one end of the outer side of the tank body 1 and is connected to a resin discharge pipe. A failed resin discharge regulating valve 501 is provided on the resin discharge pipe. The regenerated resin replenishment regulating valve 202, the resin height detection meter 302, and the system water outlet pH meter 402 are all connected to the control system 6 signal.

[0018] The water inlet 2 is located at one end of the inner side of the tank body 1 and is connected to the system water inlet distributor 203. The system water inlet distributor 203 is used as a water dispersing device to evenly disperse the replenished water and resin into the tank body 1 to avoid impact on the ion exchange resin bed 101 inside the tank body 1.

[0019] The resin height detector installation port 3 is located at one end of the inner side of the tank body 1, and a semi-enclosed structure of the resin height detector anti-interference cover 301 is provided, and the resin height detector probe 3021 is located inside the resin height detector anti-interference cover 301. The resin height detector anti-interference cover 301 is used to prevent the resin added from the water inlet 2 from affecting the measurement of the resin height detector, and to ensure that the resin layer height inside the resin height detector anti-interference cover 301 is basically consistent with the resin layer height in the ion exchange resin bed 101.

[0020] The system outlet water collector 401 is used to separate the water in the resin layer from the resin layer to form outlet water, and the system outlet water pH meter 402 is used to detect the pH value of the system outlet water.

[0021] According to the above structure, the pH adjustment method of the pH adjustable ion exchange device includes the following steps: during normal operation, the system inlet water and the regenerated resin are mixed in the system inlet pipe 201 and enter the tank body 1 from the water inlet 2, and after being fully exchanged by the ion exchange resin bed 101, they are collected by the system outlet water collector 401 and discharged from the outlet 4 to become the system outlet water, and the failed resin is discharged from the resin discharge pipe. (The failed resin enters the extracorporeal regeneration device, which does not belong to the scope of protection of the present invention, so it is not described in detail.)

[0022] The regenerated resin replenishment speed is controlled by the opening of the regenerated resin replenishment regulating valve 202, and the opening of the regenerated resin replenishment regulating valve 202 is controlled by the pH value detected by the system outlet water pH meter 402 and the control target set in the control system 6, ensuring that the pH value of the system outlet water is always close to the control target set in the control system 6.

[0023] Since copper ions in water begin to precipitate when pH>6 and are almost completely precipitated when pH>8.5, the effluent pH control target is set at 5.5.

[0024] The speed of failed resin discharge is controlled by the opening of the failed resin discharge regulating valve 501, and the opening of the failed resin discharge regulating valve 501 is controlled by the resin height detected by the resin height detector and the control target set in the control system 6, ensuring that the resin layer height of the ion exchange resin bed 101 is always close to the control target set in the control system 6.

[0025] Example

[0026] For the recovery and treatment of copper-containing wastewater with influent water quality of copper ion content ≤211ppm, TOC content ≤20ppm and pH 2-4.

[0027] The treatment method of the prior art is generally: chemical precipitation + membrane recovery. During the chemical precipitation process (i.e., adding NaOH to the water), due to the low pH of the influent, a large part of the added NaOH is consumed during the neutralization process, and only a small part can react with the copper ions in the water to form precipitation. Assuming that the pH of the influent is 2 and the copper ion content is 211 mg / L, the amount of NaOH consumed in the neutralization process is 400 mg / L, while the amount of NaOH that reacts with copper ions is only 130 mg / L. During the whole process, 530 mg / L NaOH, i.e., 0.1325 mol / L of sodium ions, will be added to the treated water, which greatly increases the salt content of the treated water.

[0028] If the pH-adjustable ion exchange device and pH-adjusting method of the present invention are used to treat the treated water, the optional treatment method is: (weakly basic ion exchange resin) pH-adjustable ion exchange + chemical precipitation + membrane recovery. First, the pH of the treated water is adjusted to about 5.5 using the pH-adjustable ion exchange device, and then NaOH is added to precipitate the copper ions in the water. Finally, the treated water is recovered using the membrane method.

[0029] In the process of treating the influent water using the pH adjustable ion exchange system, the weakly alkaline ion exchange resin in the pH adjustable ion exchange system absorbs some anions in the water and releases hydroxide ions, thereby achieving the purpose of adjusting the pH in the water. In this process, sodium ions will not be added to the water, and some anions in the water can be removed, so the salt content in the water can be reduced. After the pH of the influent water is adjusted by the pH adjustable ion exchange system, NaOH is added to the water to precipitate the copper ions in the water, and only a relatively small amount of NaOH (130 mg / L) is needed to achieve the purpose of precipitation treatment. Compared with directly adding NaOH to the water for pH adjustment precipitation, the salt content in the water after the precipitation treatment is greatly reduced, which is conducive to the subsequent membrane recovery treatment.

[0030] In the process of using ion exchange to adjust the pH of the influent, since the pH of the effluent from an ordinary anion exchange device is usually alkaline or neutral, and according to the chemical properties of copper ions, they begin to precipitate when pH>6 and almost completely precipitate when pH>8.5. Therefore, if ordinary ion exchange is used to adjust the pH value, copper ions will precipitate and clog the ion exchange tower. Therefore, ordinary ion exchange cannot be used to adjust its pH value. A pH-adjustable ion exchange system must be used to adjust the pH of the influent to ensure that precipitation and blockage will not occur in the ion exchange resin tower.

[0031] All the components mentioned above are prior art, and those skilled in the art can use any model and existing design that can achieve their corresponding functions.

[0032] The above is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several modifications and improvements without departing from the inventive concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for adjusting pH of a pH-adjustable ion exchange device, characterized in that: The pH adjustable ion exchange device comprises a carbon steel rubber lined tank body (1), the tank body (1) is filled with an ion exchange resin bed (101) composed of a weak anion exchange resin, a water inlet (2) is arranged at the top of the tank body (1), the water inlet (2) is located at one end of the outer side of the tank body (1) and is connected to a system water inlet pipe (201), the middle of the system water inlet pipe (201) is connected to a regeneration resin replenishment pipe, and a regeneration resin replenishment regulating valve (202) is arranged on the regeneration resin replenishment pipe, a resin height detector installation port (3) is arranged at the upper part of the tank body (1) through the resin height detector installation port (3), and a resin height detector probe (3021) connected to the resin height detector (302) extends to the inside of the tank body (1) through the resin height detector installation port (3), and a water outlet (4) is arranged at the lower part of the tank body (1), and the water outlet (4) is located at the lower part of the tank body (1). A system water outlet collector (401) is provided at one end of the inner side, a water outlet (4) is located at one end of the outer side of the tank body (1) and is connected to a water outlet pipe, a system water outlet pH meter (402) is provided on the water outlet pipe, a resin discharge port (5) is provided at the bottom of the tank body (1), the resin discharge port (5) is located at one end of the outer side of the tank body (1) and is connected to a resin discharge pipe, a failed resin discharge regulating valve (501) is provided on the resin discharge pipe, a regenerated resin replenishment regulating valve (202), a resin height detector (302), and a system water outlet pH meter (402) are all connected to the control system (6) by signal; the water inlet (2) is located at one end of the inner side of the tank body (1) and is connected to a system water inlet distributor (203); the resin height detector installation port (3) is located at one end of the inner side of the tank body (1), a semi-enclosed resin height detector anti-interference cover (301) is provided, and a resin height detector probe (3021) is located inside the resin height detector anti-interference cover (301); The invention comprises the following steps: during normal operation, system inlet water and regenerated resin are mixed in the system inlet pipe (201) and then enter the tank body (1) from the water inlet (2), are fully exchanged through the ion exchange resin bed (101), are collected by the system outlet water collector (401), and are discharged from the outlet (4) to become system outlet water, and the spent resin is discharged from the resin discharge pipe; the regenerated resin replenishment speed is controlled by the opening of the regenerated resin replenishment regulating valve (202), and the opening of the regenerated resin replenishment regulating valve (202) is controlled by the pH value detected by the system outlet water pH meter (402) and the control The control target set in the system (6) is jointly controlled to ensure that the pH value of the system outlet water is always close to the control target set in the control system (6); the outlet water pH control target is set to 5.5; the speed of the failed resin discharge is controlled by the opening of the failed resin discharge regulating valve (501), and the opening of the failed resin discharge regulating valve (501) is jointly controlled by the resin height detected by the resin height detector and the control target set in the control system (6), ensuring that the resin layer height of the ion exchange resin bed (101) is always close to the control target set in the control system (6).

Images