A method and apparatus for enhancing the adsorption capacity of chelating resins for metal ions.

Abstract

This invention provides a method and equipment for enhancing the adsorption capacity of chelating resin for metal ions, relating to the technical field of chlor-alkali industrial equipment. The method involves selecting chelating resin with a particle size range of 0.36-0.44 mm, feeding the chelating resin within this range into a resin absorption tower, simultaneously filling and venting the resin absorption tower, and then backwashing the chelating resin for 25-35 minutes. After backwashing, the chelating resin inside the resin absorption tower is controlled under conditions of pH 9-11 and temperature 60-80°C for the adsorption process. The equipment includes a resin absorption tower and a mobile resin addition device. Through the method and equipment of this invention, the exchange capacity of the chelating resin is effectively improved, the metal ion content in the brine is reduced, and the regeneration cycle is extended.

Description

Technical Field

[0001] This invention relates to the field of chlor-alkali industrial equipment technology, specifically to a method and equipment for improving the ability of chelating resins to adsorb metal ions. Background Technology

[0002] The chlor-alkali industry also refers to the method of producing chlorine, hydrogen, and caustic soda using saturated brine. Industrially, NaOH, Cl2, and H2 are produced by electrolyzing saturated NaCl solution, and these are used as raw materials to produce a series of chemical products; this is called the chlor-alkali industry. The chlor-alkali industry is one of the most fundamental chemical industries, and its products are widely used not only in the chemical industry itself but also in light industry, textile industry, metallurgical industry, petrochemical industry, and public utilities.

[0003] In my country, the chlor-alkali industry mainly employs two production processes: the diaphragm process and the ion-exchange membrane process. The main products of the chlor-alkali industry include caustic soda, polyvinyl chloride (PVC), chlorine, and hydrogen. Chlor-alkali products are primarily used in the manufacture of organic chemicals, papermaking, soap making, glass, synthetic fibers, and plastics.

[0004] In recent years, China's chlor-alkali industry has developed rapidly. Existing chlor-alkali enterprises have expanded their production capacity, and new enterprises have also started production one after another, resulting in a rapid increase in capacity. The chlor-alkali industry is showing a trend of accelerating development towards large-scale and high-tech production. While the production capacity of China's chlor-alkali industry has increased rapidly, its technology has also made great strides, with more large-scale plants and improved plant technology levels. China's chlor-alkali industry is developing towards large-scale and high-tech production.

[0005] Due to the special nature of electrolyzer equipment, the quality requirements for the influent are high, especially regarding the content of metal ions (calcium, magnesium, etc.). Therefore, a resin tower is usually installed before the electrolyzer, filled with chelating resin to reduce the metal ion content in the brine. Existing chelating resins are mostly large-particle-size, with small exchange capacity and short regeneration cycles.

[0006] Therefore, there are areas for improvement. The present invention provides a method and apparatus for enhancing the ability of chelating resin to adsorb metal ions. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to propose a method for enhancing the adsorption capacity of chelating resins for metal ions, the specific solution of which is as follows:

[0008] A method for improving the adsorption capacity of chelating resin for metal ions involves selecting chelating resin with a particle size in the range of 0.36-0.44 mm, feeding the chelating resin with a particle size within the range into a resin absorption tower, simultaneously filling the resin absorption tower with water and venting the air, then backwashing the chelating resin for 25-35 minutes. After backwashing, the chelating resin inside the resin absorption tower is controlled under conditions of pH 9-11 and temperature 60-80℃ for the adsorption process.

[0009] Furthermore, when the chelating resin is fed into the resin absorption tower, it is flushed with water at a pressure of 0.4 MPa, and the chelating resin is simultaneously flushed into the resin absorption tower.

[0010] Furthermore, the chelating resin capacity in the resin absorption tower reaches 70-90%.

[0011] A device for enhancing the adsorption capacity of chelating resin for metal ions, the device comprising the resin absorption tower, the resin absorption tower being provided with a conveying hole, a water distributor, a water outlet valve, and an air vent valve, the water distributor being provided with a water inlet valve, the device further comprising a movable resin adding device for cooperating with the conveying hole.

[0012] Furthermore, the resin absorption tower is equipped with a filter component inside, and the filter component is embedded with multiple filter caps that are evenly distributed.

[0013] Furthermore, an adjustable discharge gap is formed between the filter components and the inner wall of the resin absorption tower.

[0014] Furthermore, the width of the unloading gap ranges from 0.3 to 0.6 mm.

[0015] Furthermore, the mobile resin addition device includes a resin funnel, an injector, a quick connector, a mobile trolley, and a transfer hose;

[0016] The injector is fixedly mounted on the mobile trolley, and the discharge port of the resin funnel is equipped with a double-ended interface, which is connected to the injector and the quick connector respectively.

[0017] The other end of the injector is connected to a transfer hose, and a quick connector is used to connect to a 0.4MPa water source.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] (1) In this invention, by adding small-particle-size chelating resin in the resin absorption tower, the exchange capacity of the resin can be increased and the regeneration cycle can be extended. When an adsorption process is required, the primary brine is first flowed through the resin absorption tower of this invention and then enters the electrolytic cell for electrolysis to produce products.

[0020] Under the set conditions, the brine after passing through the resin absorption tower of the present invention can adsorb more metal ions. The lower the metal ion content in the brine, the less damage to the electrolytic cell, and the higher the quality of the produced product.

[0021] (2) By setting up a resin absorption tower and a mobile resin adding device, the chelating resin can be continuously transported into the resin absorption tower, which is convenient to operate and saves manpower. Attached Figure Description

[0022] Figure 1 This is an overall schematic diagram of the resin absorption tower of the present invention;

[0023] Figure 2 A schematic diagram showing the connection between the resin absorption tower and the mobile resin addition device;

[0024] Figure 3 A cross-sectional schematic diagram showing the discharge orifice of the resin absorption tower.

[0025] Reference numerals: 1. Resin absorption tower; 2. Conveying port; 3. Water distributor; 4. Outlet valve; 5. Air vent valve; 6. Inlet valve; 7. Mobile resin adding device; 71. Resin funnel; 72. Injector; 73. Quick connector; 74. Mobile trolley; 75. Transfer hose; 8. Discharge gap; 9. Filter component; 91. Protrusion; 10. Filter cap. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0027] Based on the deficiencies existing in the chlor-alkali industry, this invention proposes a method to improve the adsorption capacity of chelating resins for metal ions, which is mainly achieved by reducing the particle size.

[0028] Specifically, the method is as follows: Select chelating resin with a particle size in the range of 0.36-0.44 mm, send the chelating resin with a particle size in the range into resin absorption tower 1, and at the same time fill the resin absorption tower 1 with water and vent the air. Then backwash the chelating resin for 25-35 minutes. After the backwash is completed, control the chelating resin inside the resin absorption tower 1 to be under the conditions of pH 9-11 and temperature 60-80℃ for adsorption process.

[0029] It should be noted that this type of resin absorption tower 1 is suitable for the chlor-alkali industry in the chemical industry, especially for the step of pretreatment of primary brine before electrolysis, so as to reduce the metal ions in the primary brine, meet the influent standards of the electrolysis cell, and reduce damage to the electrolysis cell.

[0030] The preferred particle size of the chelating resin is 0.4 mm. In the prior art, the particle size of chelating resin is generally around 0.63 mm. Compared to the prior art, the chelating resin of this invention has a smaller particle size and a larger specific surface area, allowing for more contact between the resin and the primary brine, increasing the resin's exchange capacity and the diffusion rate of the primary brine. In this way, the chelating resin in the resin absorption tower 1 can adsorb more metal ions from the primary brine.

[0031] Secondly, when the pH is between 9 and 11 and the temperature is between 60 and 80°C, without affecting the stability of the chelating resin, this pH value and temperature can increase the rate of ion exchange and improve the ion selective adsorption capacity of the chelating resin.

[0032] It should be noted that when the chelating resin is fed into the resin absorption tower 1, it is flushed with water at a pressure of 0.4 MPa, and the chelating resin is flushed into the resin absorption tower 1 at the same time.

[0033] It should be noted that the chelating resin capacity in resin absorption tower 1 reaches 70-90%, which ensures sufficient contact time between the brine and the chelating resin.

[0034] Meanwhile, the present invention also provides a device for improving the ability of chelating resin to adsorb metal ions, the device comprising a resin absorption tower 1 and a mobile resin adding device 7.

[0035] like Figure 1 The resin absorption tower 1 can adopt an existing structure. To achieve the necessary functions of the resin absorption tower 1, it is equipped with a conveying hole 2, a water distributor 3, a water outlet valve 4, and an air vent valve 5. The water distributor 3 is equipped with an inlet valve 6, both located at the top of the resin absorption tower 1. The water distributor 3 and the inlet valve 6 work together to supply water to the resin absorption tower 1. The water outlet valve 4 is located at the bottom of the resin absorption tower 1 for drainage, and the air vent valve 5 is located at the top of the resin absorption tower 1 for venting.

[0036] The conveying hole 2 is located on the side of the resin absorption tower 1 and is used to cooperate with the mobile resin adding device 7 to fill the interior of the resin absorption tower 1 with chelating resin.

[0037] like Figure 2 Specifically, the mobile resin adding device 7 includes a resin funnel 71, an injector 72, a quick connector 73, a mobile trolley 74, and a transfer hose 75. The injector 72 is fixedly mounted on the mobile trolley 74. The discharge port of the resin funnel 71 is equipped with a double-ended interface, which is connected to the injector 72 and the quick connector 73 respectively. The other end of the injector 72 is connected to the transfer hose 75. The quick connector 73 is used to connect to a 0.4MPa water source.

[0038] Before filling the chelating resin, empty the inside of the resin absorption tower 1, remove all internal residues, open the conveying hole 2, check whether the internal parts of the equipment are damaged, and ensure that there is no resin leakage. Fill the resin absorption tower 1 with water from the top to about 1 / 3 of the equipment height.

[0039] When chelating resin needs to be filled, connect a 0.4MPa water source to the quick connector 73 and insert the transfer hose 75 into the delivery hole 2. Open the water source valve to establish a hydraulic jet circulation, pour the chelating resin of appropriate particle size into the resin funnel 71, and use the vacuum suction effect of the resin ejector 72 to draw the chelating resin into the resin absorption tower 1.

[0040] After the chelating resin is filled, close the delivery port 2. Generally, replace the gasket in delivery port 2. Open the vent valve 5 and the water inlet valve 6 to fill the resin absorption tower 1 with water. After water overflows from the vent valve 5, close the vent valve 5 to stop the top water intake. Then, backwash the chelating resin for 30 minutes.

[0041] like Figure 3 It should be noted that in order to ensure that the resin absorption tower 1 can maintain a certain flow rate and prevent the chelating resin inside from flowing out, the resin absorption tower 1 is equipped with a filter component 9, which is set close to the bottom. The filter component 9 is generally disc-shaped, and its outer surface is welded to the inside of the resin absorption tower 1 by forming multiple protrusions 91. Multiple uniformly distributed filter caps 10 are embedded on the top surface. The filter caps 10 have an existing structure. The liquid can flow away from the filter caps 10, while the chelating resin will be blocked by the filter caps 10. They are also used to help complete the backwashing of the chelating resin.

[0042] In an optimized configuration, a discharge gap 8 is formed between the filter element 9 and the inner wall of the resin absorption tower 1, used to remove the chelating resin that needs to be replaced from the resin absorption tower 1. Due to the setting of the protrusion 91, several discharge gaps 8 are formed around the circumference of the filter element 9. The size of the discharge gap 8 is adjustable, and the width of the discharge gap 8 ranges from 0.3 to 0.6 mm. When the resin absorption tower 1 is working normally, the width of the discharge gap 8 is set to 0.3 mm, which is smaller than the particle size of the chelating resin to prevent the chelating resin from falling. When the chelating resin in the resin absorption tower 1 needs to be replaced, the width of the discharge gap 8 is set to 0.5 mm or 0.6 mm, which is larger than the particle size of the chelating resin, so that the chelating resin can fall to the bottom of the resin absorption tower 1 and then be discharged.

[0043] The discharge orifice 8 can be adjusted by embedding an elastic rubber strip in the outer edge of the filter element. When the rubber strip is pressed by the worker with a support rod and compressed in the outer edge of the filter element, the width of the discharge orifice 8 increases. When the support rod is removed, the rubber strip can be released, thereby reducing the width of the discharge orifice 8.

[0044] Based on the above, the present invention proposes the following embodiments and comparative examples. The chelating resin and reaction conditions inside the resin absorption tower 1 in each embodiment and comparative example are different. A single brine solution is used to perform the adsorption process in the embodiments and comparative examples, and tests are conducted. The details are described below:

[0045] Feed parameters for primary brine A:

[0046] NaCl (g / L) 300 Ca + Mg(ppb) 583 Sr(ppb) 115 Ba(ppb) 98 Fe(ppb) 10 pH 9 Free chlorine 0

[0047] Based on the aforementioned primary saline solution A, Examples 1 to 4, and Comparative Examples 1 to 3 are proposed.

[0048] Example 1: Select chelating resin with a particle size in the range of 0.36 mm, and feed the chelating resin with a particle size in the range into resin absorption tower 1. At the same time, fill the resin absorption tower 1 with water and vent the air. Then backwash the chelating resin for 30 minutes. After the backwash is completed, control the chelating resin inside the resin absorption tower 1 to be under the conditions of pH 9 and temperature 60°C for the adsorption process.

[0049] Example 2: The difference from Example 1 is that the chelating resin used is 0.4 mm, the pH value is 10, and the temperature is 70°C.

[0050] Example 3: The difference from Example 1 is that the chelating resin used is 0.4 mm, the pH value is 11, and the temperature is 80℃.

[0051] Example 4: The difference from Example 1 is that the chelating resin used is 0.44mm, the pH value is 11, and the temperature is 80℃.

[0052] Comparative Example 1: The difference from Example 4 is that the chelating resin used is 0.32mm, the pH value is 11, and the temperature is 80℃.

[0053] Comparative Example 2: The difference from Example 4 is that the chelating resin used is 0.48 mm, the pH value is 11, and the temperature is 80°C.

[0054] Comparative Example 3: The difference from Example 4 is that the chelating resin used is 0.6 mm, the pH value is 11, and the temperature is 80°C.

[0055] In Examples 1 to 4, and Comparative Examples 1 to 3, after adsorption of the aforementioned primary brine A, the outlet parameters of resin absorption tower 1 were tested, and the specific results are as follows:

[0056] Table 1

[0057]

[0058] As shown in Table 1, among Examples 1 to 4, the concentration of metal ions was lowest in Example 3. Specifically, comparing Example 2 with Example 1, it can be seen that when the particle size of the chelating resin increases, the pH value and temperature are higher, the concentration of metal ions in the primary brine A after leaving resin absorption tower 1 decreases; comparing Example 3 with Example 2, it can be seen that when the particle size of the chelating resin is the same, the pH value and temperature are higher, the concentration of metal ions in the primary brine A after leaving resin absorption tower 1 decreases.

[0059] As can be seen from Example 4 compared to Example 3, when the chelating resin particle size is larger and the pH value and temperature are consistent, the concentration of metal ions in the primary brine A after leaving resin absorption tower 1 does not decrease, but rather increases. Furthermore, considering Comparative Examples 1 to 3, when the pH value and temperature are consistent, whether the chelating resin particle size is smaller than or larger than the particle size range of the chelating resin of this invention, the concentration of metal ions in the primary brine A after leaving resin absorption tower 1 is greater than the values ​​in the embodiments of this invention.

[0060] It is known that a larger particle size of the chelating resin will affect the concentration of metal ions in the primary brine A after leaving the resin absorption tower 1. Furthermore, in this invention, the particle size of the chelating resin is not necessarily better the smaller it is; it is preferably 0.4 mm, and the pH value and temperature are preferably 11 and 80°C, respectively.

[0061] Furthermore, this invention also used different primary saline solutions to test the best-performing Example 3, as detailed below:

[0062] Primary brine feed index B

[0063] NaCl (g / L) 300 Ca + Mg(ppb) 1296 Sr(ppb) 889 Ba(ppb) 279 Fe(ppb) 12 pH 9 Free chlorine 0

[0064] Primary brine feed C index

[0065] NaCl (g / L) 300 Ca + Mg(ppb) 114 Sr(ppb) 98 Ba(ppb) 102 Fe(ppb) 10 pH 9 Free chlorine 0

[0066] Primary brine feed index D

[0067]

[0068]

[0069] Table 2

[0070]

[0071] As shown in Table 2, when the chelating resin particle size, pH value and temperature of primary brine B, C and D are set in resin absorption tower 1 according to the method of Example 3, the concentration of metal ions in the primary brine after passing through resin absorption tower 1 is greatly reduced.

[0072] In summary, the use of small-particle-size chelating resins in this invention can reduce the metal ion content in the primary brine to a certain extent, resulting in better product quality and less damage to the electrolyzer. Correspondingly, the regeneration cycle of the chelating resins in the various embodiments is also extended; the higher the quality of the primary brine, the longer the regeneration cycle can be extended, in practice, by 3-10 days.

[0073] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for improving the ability of a chelating resin to adsorb metal ions, characterized by, Select chelating resin with a particle size of 0.4 mm, and feed the chelating resin with a particle size within the specified range into the resin absorption tower (1). At the same time, fill the resin absorption tower (1) with water and vent the air. Then, backwash the chelating resin for 25-35 minutes. After backwashing, control the chelating resin inside the resin absorption tower (1) to be under the conditions of pH 9-11 and temperature 60-80℃ for adsorption. The above method uses the following equipment, which includes the resin absorption tower (1). The resin absorption tower (1) is provided with a conveying hole (2), a water distributor (3), a water outlet valve (4), and an air vent valve (5). The water distributor (3) is provided with a water inlet valve (6). Its features are as follows: The device further includes a mobile resin adding device (7) for cooperating with the conveying hole (2); the resin absorption tower (1) is provided with a filter component (9) inside, and multiple uniformly distributed filter caps (10) are embedded on the filter component (9); an adjustable discharge gap (8) is also formed between the filter component (9) and the inner wall of the resin absorption tower (1); the width of the discharge gap (8) is in the range of 0.3-0.6mm; the mobile resin adding device (7) includes a resin funnel (71), an injector (72), a quick connector (73), a mobile trolley (74), and a transfer hose (75); The injector (72) is fixedly installed on the mobile trolley (74), and the discharge port of the resin funnel (71) is equipped with a double-headed interface, which is connected to the injector (72) and the quick connector (73) respectively. The other end of the injector (72) is connected to the transfer hose (75), and the quick connector (73) is used to connect to a 0.4MPa water source.

2. The method of claim 1, wherein the method is characterized by, When the chelating resin is fed into the resin absorption tower (1), it is flushed with water at a pressure of 0.4 MPa, and the chelating resin is flushed into the resin absorption tower (1) at the same time.

3. The method of claim 2, wherein the method is characterized by, The chelating resin capacity in the resin absorption tower (1) reaches 70-90%.

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