Method and system for treating coking nanofiltration concentrate water

Abstract

This invention relates to the field of water treatment technology, and more particularly to a method and system for treating coking nanofiltration concentrate. The method includes: pre-configuring a modified nickel plate anode electrode, a modified titanium plate cathode electrode, and multi-media filter media according to the water quality characteristics of the coking nanofiltration concentrate; feeding the coking nanofiltration concentrate into an electrocatalytic oxidation device for treatment, wherein the electrocatalytic oxidation device uses the modified nickel plate anode electrode as the anode electrode and the modified titanium plate cathode electrode as the cathode electrode; and pumping the effluent from the electrocatalytic oxidation device into a multi-media filter for filtration, wherein the multi-media filter contains multi-media filter media. By first subjecting the coking nanofiltration concentrate to electrocatalytic oxidation treatment, Cl... ‑ The anode loses electrons and is oxidized, producing a large number of active chlorine and other free radicals, which can rapidly degrade ammonia nitrogen. This allows relatively stable substances to react, and then a multi-media filter is used for filtration, which can economically and efficiently remove COD and ammonia nitrogen from coking nanofiltration concentrate.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and in particular to a method and system for treating coking nanofiltration concentrate. Background Technology

[0002] Coking is a typical "high-energy-consuming, high-polluting, and resource-intensive" industry. The production of coke generates a large amount of wastewater; my country discharges approximately 100 million tons of coking wastewater annually. Coking wastewater is formed during the high-temperature dry distillation of coal, as well as the purification of coal gas and the refining of chemical products. It contains dozens of pollutants, including phenols, ammonia nitrogen, cyanide, benzene, pyridine, indole, and quinoline. Its composition is complex, with high concentrations of organic pollutants, high color, and high toxicity. It is also very stable and is a typical type of recalcitrant organic wastewater.

[0003] Currently, the national standards for wastewater discharge and related "energy conservation and emission reduction" policies are gradually being raised. On October 1, 2012, a new "Emission Standard for Pollutants from Coking Chemical Industry" (GB16171-2012) was promulgated. The "Emission Standard for Pollutants from Coking Chemical Industry" requires that, from January 1, 2015, existing enterprises must implement standards of 40 mg / L for COD, 0.2 mg / L for cyanide ions, and 10 mg / L for fluoride ions. At the same time, there are strict requirements for ammonia nitrogen, total nitrogen, petroleum hydrocarbons, volatile phenols, sulfides, polycyclic aromatic hydrocarbons (PAHs), benzo(a) benzo[a] ...

[0004] Wastewater reuse is the ultimate goal of wastewater treatment and a means for enterprises to achieve energy conservation and emission reduction. Currently, simple coking wastewater reuse technologies are no longer sufficient to meet the requirements of enterprises, making advanced treatment of biochemically treated coking wastewater for reuse an inevitable trend. Domestic coking wastewater treatment technology uses nanofiltration to treat coking wastewater for reuse as circulating cooling water in steel enterprises. However, the main problem lies in the treatment of the concentrated water generated by nanofiltration. Therefore, if the concentrated water generated by the nanofiltration process is discharged directly without treatment, it will inevitably cause great harm to the aquatic environment. Summary of the Invention

[0005] The purpose of this invention is to provide a method and system for treating coking nanofiltration concentrate, so as to solve the existing problems in the treatment of coking nanofiltration concentrate.

[0006] To achieve the above objectives, the present invention provides a method for treating coking nanofiltration concentrate, comprising:

[0007] Modified nickel plate anode electrode, modified titanium plate cathode electrode, and multi-media filter media were pre-configured to meet the water quality characteristics of coking nanofiltration concentrate.

[0008] The coking nanofiltration concentrate is fed into an electrocatalytic oxidation device for treatment. The electrocatalytic oxidation device uses the modified nickel plate anode electrode as the anode electrode and the modified titanium plate cathode electrode as the cathode electrode.

[0009] The effluent from the electrocatalytic oxidation device is fed into a multi-media filter for filtration, and the multi-media filter contains the multi-media filter media.

[0010] Optionally, the method for preparing the modified nickel plate anode electrode includes:

[0011] Select a nickel plate with a thickness of 1 mm, immerse it in a sulfuric acid solution with a mass percentage of 4-7% for 34-39 minutes to remove surface metal oxides, rinse it with pure water 3-5 times after removal, immerse the nickel plate in methanol for 20-25 minutes to remove surface organic matter, rinse it with pure water 3-5 times after removal, and then place the nickel plate in a vacuum drying oven.

[0012] Prepare a copper chloride solution of 1.9–3.8 mol / L by adding 45–56 mg of manganese nitrate to each liter of the copper chloride solution to form a mixed copper chloride solution;

[0013] The nickel plate is immersed in the copper chloride mixed solution, placed in a hydrothermal reactor, heated to 170-230°C, reacted for 690-780 minutes, and then cooled before being removed.

[0014] The nickel plate is placed in a tube furnace and heated to 196-213°C at a rate of 2-4°C / min under an argon atmosphere. It is then held at this temperature for 345-490 min for vacuum carbonization. Finally, it is cooled to room temperature to obtain the modified nickel plate anode electrode.

[0015] Optionally, the method for preparing the modified titanium plate cathode electrode includes:

[0016] Select a titanium plate with a thickness of 1 mm, immerse it in a hydrochloric acid solution with a mass percentage of 1-3% for 41-45 minutes to remove surface metal oxides, rinse it with pure water 3-5 times after removal, immerse the titanium plate in petroleum ether for 26-35 minutes to remove surface organic matter, rinse it with pure water 3-5 times after removal, and then put the titanium plate into a vacuum drying oven.

[0017] Prepare a manganese sulfate solution with a concentration of 459–978 mg / L by adding 21–26 mg of manganese chloride to each liter of the manganese sulfate solution and sonicating for 20–35 min to form a manganese sulfate mixed solution.

[0018] The titanium plate is immersed in the manganese sulfate mixed solution for 450-490 min, then placed in a muffle furnace, and the temperature of the muffle furnace is increased to 511-527°C at 5-8°C / min, held at the temperature for 65-75 min, and then cooled to room temperature to prepare the modified titanium plate cathode electrode.

[0019] Optionally, the distance between the modified nickel plate anode electrode and the modified titanium plate cathode electrode is 2–2.5 cm, and the current density is 5.1–6.3 A / m. 2 .

[0020] Optionally, the multi-media filter media is composed of ceramsite, activated carbon particles, and water sludge, with the ceramsite placed in the lower layer of the multi-media filter, the activated carbon particles placed in the middle layer of the multi-media filter, and the water sludge placed in the upper layer of the multi-media filter.

[0021] Optionally, the porosity of the ceramsite is 66-68%, and the density is 502-506 kg / m³. 3 This accounts for 10% of the total volume of the multi-media filter media.

[0022] Optionally, the activated carbon particles have a particle size of 200-300 mesh and a specific surface area of ​​1250-1360 m². 2 / g, with an iodine value of 800-950 mg / g, accounting for 50% of the total volume of the multi-media filter media.

[0023] Optionally, the particle size of the water slag is 200-300 mesh. The water slag is the molten slag from the blast furnace during ironmaking, which is a granular solid residue produced after water quenching. The uniformity is 85%-98%, accounting for 40% of the total volume of the multi-media filter media.

[0024] Optionally, the hydraulic residence time of the coking nanofiltration concentrate in the electrocatalytic oxidation device is 123–178 min, and the hydraulic residence time of the coking nanofiltration concentrate in the multi-media filter is 45–70 min.

[0025] Based on the same inventive concept, the present invention also provides a coking nanofiltration concentrate treatment system for implementing the coking nanofiltration concentrate treatment method described above, including a dosing unit, an electrocatalytic oxidation device, and a multi-media filter.

[0026] The dosing unit is used to pre-configure modified nickel plate anode electrode, modified titanium plate cathode electrode, and multi-media filter media according to the water quality characteristics of coking nanofiltration concentrate.

[0027] The electrocatalytic oxidation device is used to electrocatalytically oxidize the coking nanofiltration concentrate. The electrocatalytic oxidation device uses the modified nickel plate anode electrode as the anode electrode and the modified titanium plate cathode electrode as the cathode electrode.

[0028] The multi-media filter is used to filter the effluent from the electrocatalytic oxidation device, and the multi-media filter contains the multi-media filter media.

[0029] In the coking nanofiltration concentrate treatment method and system provided by the present invention, the coking nanofiltration concentrate is first subjected to electrocatalytic oxidation treatment, Cl - The anode loses electrons and is oxidized, generating a large number of active chlorine and other free radicals, which can rapidly degrade ammonia nitrogen. This allows relatively stable substances to react, and then the solution is filtered using a multi-media filter 6, which can economically and efficiently remove COD and ammonia nitrogen from the coking nanofiltration concentrate. Furthermore, the modified nickel plate has an increased peak current density, which can improve the direct oxidation capacity of organic compounds and the indirect oxidation capacity of hydroxyl free radicals generated by hydrolysis. The modified titanium plate cathode electrode can reduce the occurrence of oxygen evolution side reactions at the anode, which not only promotes the generation of hydroxyl ions that enhance oxidation, but also reduces electrode passivation, improves corrosion resistance, and thus increases the electrode's service life. Attached Figure Description

[0030] Those skilled in the art will understand that the accompanying drawings are provided to better understand the invention and do not constitute any limitation on the scope of the invention. Wherein:

[0031] Figure 1 A flowchart of a coking nanofiltration concentrate treatment method provided in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of a coking nanofiltration concentrate treatment system provided in an embodiment of the present invention.

[0033] in:

[0034] 1- Primary inlet pump; 2- Electrocatalytic oxidation device; 3- Modified nickel plate anode electrode; 4- Modified titanium plate cathode electrode; 5- Secondary inlet pump; 6- Multi-media filter; 7- Multi-media filter media; 8- Outlet pump. Detailed Implementation

[0035] To make the objectives, advantages, and features of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clearly illustrate the purpose of the embodiments of this invention. Please refer to the accompanying drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only used to complement the content disclosed in the specification, for those skilled in the art to understand and read, and are not intended to limit the implementation conditions of this invention. Any modifications to the structure, changes in proportions, or adjustments to the size, if they are the same as or similar to the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention.

[0036] As used herein, the singular forms “a,” “an,” and “the” include plural objects unless otherwise expressly indicated. As used herein, the term “or” is generally used to include “and / or” unless otherwise expressly indicated. As used herein, the term “a number” is generally used to include “at least one” unless otherwise expressly indicated. As used herein, the term “at least two” is generally used to include “two or more” unless otherwise expressly indicated. Furthermore, the terms “first,” “second,” and “third” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as “first,” “second,” or “third” may explicitly or implicitly include one or at least two of that feature.

[0037] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to a connection within two components or an interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0038] Please refer to Figure 1 and Figure 2 This embodiment provides a method for treating coking nanofiltration concentrate, including the following steps:

[0039] S1. Modified nickel plate anode electrode 3, modified titanium plate cathode electrode 4, and multi-media filter media 7 are pre-configured according to the water quality characteristics of coking nanofiltration concentrate.

[0040] S2. The coking nanofiltration concentrate is fed into the electrocatalytic oxidation unit 2 for treatment. The electrocatalytic oxidation unit 2 uses a modified nickel plate anode electrode 3 as the anode electrode and a modified titanium plate cathode electrode 4 as the cathode electrode.

[0041] S3. The effluent from the electrocatalytic oxidation device 2 is fed into the multi-media filter 6 for filtration. The multi-media filter 6 contains multi-media filter media 7.

[0042] By first treating the coking nanofiltration concentrate with electrocatalytic oxidation, Cl - The anode loses electrons and is oxidized, generating a large number of active chlorine and other free radicals, which can rapidly degrade ammonia nitrogen. This allows relatively stable substances to react, and then the solution is filtered by a multi-media filter 6, which can economically and efficiently remove COD and ammonia nitrogen from the coking nanofiltration concentrate. Furthermore, the modified nickel plate has an increased peak current density, which can improve the direct oxidation ability of organic compounds and the indirect oxidation ability of hydroxyl free radicals generated by hydrolysis. The modified titanium plate cathode electrode 4 can reduce the occurrence of oxygen evolution side reactions at the anode, which not only promotes the generation of hydroxide ions that enhance oxidation, but also reduces electrode passivation, improves corrosion resistance, and thus increases the service life of the electrode.

[0043] First, execute S1, and pre-configure the modified nickel plate anode electrode 3, the modified titanium plate cathode electrode 4, and the multi-media filter media 7 according to the water quality characteristics of the coking nanofiltration concentrate.

[0044] In this embodiment, the water quality characteristics of the coking nanofiltration concentrate are as follows: conductivity 21200~35700μS / cm, sulfate ion 1231~1452mg / L, COD 234~363mg / L, and ammonia nitrogen 23~32mg / L.

[0045] Preferably, the preparation method of the modified nickel plate anode electrode 3 includes:

[0046] Select a nickel plate with a thickness of 1 mm, immerse it in a sulfuric acid solution with a mass percentage of 4-7% for 34-39 minutes to remove surface metal oxides, rinse it with pure water 3-5 times after removal, immerse the nickel plate in methanol for 20-25 minutes to remove surface organic matter, rinse it with pure water 3-5 times after removal, and then put the nickel plate into a vacuum drying oven.

[0047] To prepare a copper chloride solution of 1.9–3.8 mol / L, add 45–56 mg of manganese nitrate to each liter of copper chloride solution to form a mixed copper chloride solution.

[0048] The nickel plate was immersed in a copper chloride mixed solution and placed in a hydrothermal reactor. The hydrothermal reactor was heated to 170-230°C and reacted for 690-780 minutes. The nano-copper manganese particles adhered to the surface of the nickel electrode. After cooling, the nickel plate was removed.

[0049] The nickel plate was placed in a tube furnace and heated to 196–213°C at a rate of 2–4°C / min under an argon atmosphere. It was then held for 345–490 min for vacuum carbonization and cooled to room temperature to obtain the modified nickel plate anode electrode 3.

[0050] In this embodiment, the peak current density of the unmodified nickel plate electrode is 35–42 mA / cm². 2 After modification, the peak current density of the modified nickel plate anode electrode 3 is 151–158 mA / cm². 2 The increased peak current density of the modified nickel plate anode electrode 3 can enhance the direct oxidation ability of organic compounds and also improve the indirect oxidation ability of hydroxyl radicals generated by hydrolysis.

[0051] Preferably, the preparation method of the modified titanium plate cathode electrode 4 includes:

[0052] Select a titanium plate with a thickness of 1 mm, immerse it in a hydrochloric acid solution with a mass percentage of 1-3% for 41-45 minutes to remove surface metal oxides, rinse it with pure water 3-5 times after removal, immerse the titanium plate in petroleum ether for 26-35 minutes to remove surface organic matter, rinse it with pure water 3-5 times after removal, and then put the titanium plate into a vacuum drying oven.

[0053] To prepare a manganese sulfate solution with a concentration of 459–978 mg / L, add 21–26 mg of manganese chloride to each liter of manganese sulfate solution and sonicate for 20–35 minutes to form a mixed manganese sulfate solution.

[0054] The titanium plate was immersed in a manganese sulfate mixed solution for 450–490 min, then placed in a muffle furnace. The muffle furnace was heated to 511–527 °C at a rate of 5–8 °C / min, held at that temperature for 65–75 min, and then cooled to room temperature to prepare the modified titanium plate cathode electrode 4.

[0055] The modified titanium plate cathode electrode 4 can reduce the occurrence of the anolyte oxygen evolution side reaction. This not only promotes the generation of hydroxyl ions, which enhance oxidation, but also reduces electrode passivation and improves corrosion resistance, thereby increasing the electrode's service life. In coking nanofiltration concentrate, the standard potential of the unmodified titanium plate is +0.23V, while the standard potential of the modified titanium plate cathode electrode 4 is +0.11V, indicating that the modified titanium plate cathode electrode 4 has strong adhesion, good protection, and good corrosion resistance.

[0056] Preferably, the multi-media filter media 7 is composed of ceramsite, activated carbon particles and water sludge. The ceramsite is placed in the lower layer of the multi-media filter 6, the activated carbon particles are placed in the middle layer of the multi-media filter 6, and the water sludge is placed in the upper layer of the multi-media filter 6.

[0057] The porosity of expanded clay aggregate is 66-68%, and its density is 502-506 kg / m³. 3 It accounts for 10% of the total volume of the multi-media filter media 7.

[0058] The particle size of activated carbon is 200-300 mesh, and the specific surface area is 1250-1360 m². 2 / g, with an iodine value of 800-950mg / g, accounting for 50% of the total volume of the multi-media filter media 7.

[0059] The particle size of the water slag is 200-300 mesh. Water slag is the granular solid residue produced by water quenching of molten slag from the blast furnace during ironmaking. Its uniformity is 85%-98%, accounting for 40% of the total volume of the multi-media filter media 7.

[0060] After configuring the modified nickel plate anode electrode 3, the modified titanium plate cathode electrode 4, and the multi-media filter media 7, execute S2 to send the coking nanofiltration concentrate into the electrocatalytic oxidation unit 2 for treatment. The electrocatalytic oxidation unit 2 uses the modified nickel plate anode electrode 3 as the anode electrode and the modified titanium plate cathode electrode 4 as the cathode electrode.

[0061] In this embodiment, the coking nanofiltration concentrate enters the electrocatalytic oxidation unit 2 via a primary feed pump 1. A modified nickel plate anode electrode 3 and a modified titanium plate cathode electrode 4 are placed on the upper part of the electrocatalytic oxidation unit 2. Electrocatalytic oxidation directly generates hydroxide ions through electrolysis, which not only attacks dissolved oxygen- or oxygen-free organic matter but also acts on nitrogen-containing substances, leading to chain scission, oxidation, and even mineralization, generating CO2. During the electrocatalytic oxidation process of the coking nanofiltration concentrate, Cl... - The anode loses electrons and is oxidized, generating a large number of active chlorine and other free radicals, which can rapidly degrade ammonia nitrogen, causing relatively stable substances to react. During operation, the hydraulic residence time is 123–178 min, the distance between the modified nickel plate anode electrode 3 and the modified titanium plate cathode electrode 4 is 2–2.5 cm, and the current density is 5.1–6.3 A / m. 2 .

[0062] After electro-oxidation, the concentrated coking nanofiltration water has a conductivity of 21200–35700 μS / cm, a sulfate ion concentration of 1231–1452 mg / L, a COD concentration of 66–87 mg / L, and an ammonia nitrogen concentration of 3–6 mg / L.

[0063] Finally, S3 is executed, which pumps the effluent from the electrocatalytic oxidation device 2 into the multi-media filter 6 for filtration. The multi-media filter 6 contains multi-media filter media 7.

[0064] In this embodiment, coking nanofiltration concentrate is pumped into multi-media filter 6 via a secondary inlet pump 5. Multi-media filter media 7 occupies 80-88% of the total volume of multi-media filter 6, and the residence time of the coking nanofiltration concentrate in multi-media filter 6 is 45-70 minutes. Based on mechanisms such as over-interception and adsorption, multi-media filter media 7 can significantly improve water transparency and reduce turbidity, resulting in clearer water.

[0065] The coking nanofiltration concentrate is filtered through a multi-media filter 6 and then discharged by an outlet pump 8. After treatment, the coking nanofiltration concentrate has a conductivity of 21200–35700 μS / cm, a sulfate ion concentration of 1231–1452 mg / L, a COD concentration of 29–36 mg / L, and an ammonia nitrogen concentration of 2–4 mg / L.

[0066] Based on the same technical concept, embodiments of the present invention also provide a coking nanofiltration concentrate treatment system for implementing the above-mentioned coking nanofiltration concentrate treatment method, such as... Figure 2 As shown, the coking nanofiltration concentrate treatment system includes a dosing unit, an electrocatalytic oxidation device 2, and a multi-media filter 6.

[0067] The dosing unit is used to pre-configure the modified nickel plate anode electrode 3, the modified titanium plate cathode electrode 4, and the multi-media filter media 7 according to the water quality characteristics of the coking nanofiltration concentrate.

[0068] Electrocatalytic oxidation device 2 is used to electrocatalytically oxidize coking nanofiltration concentrate. The electrocatalytic oxidation device 2 uses a modified nickel plate anode electrode 3 as the anode electrode and a modified titanium plate cathode electrode 4 as the cathode electrode.

[0069] The multi-media filter 6 is used to filter the effluent from the electrocatalytic oxidation device 2. The multi-media filter 6 contains multi-media filter media 7.

[0070] The technical concept of the present invention will be further illustrated below through three specific embodiments.

[0071] Example 1

[0072] In this embodiment, the water quality characteristics of the coking nanofiltration concentrate are as follows: conductivity 35700 μS / cm, sulfate ion 1452 mg / L, COD 363 mg / L, and ammonia nitrogen 32 mg / L.

[0073] The modified nickel plate anode electrode 3 is prepared based on the characteristics of coking nanofiltration concentrate, and its preparation method is as follows:

[0074] Select a nickel plate with a thickness of 1 mm, immerse it in a sulfuric acid solution with a mass percentage of 7% for 39 minutes to remove surface metal oxides, rinse it with pure water 5 times after removal, immerse the nickel plate in methanol for 25 minutes to remove surface organic matter, rinse it with pure water 5 times after removal, and then put the nickel plate into vacuum drying.

[0075] To prepare a 3.8 mol / L copper chloride solution, add 56 mg of manganese nitrate to each liter of copper chloride solution to form a mixed copper chloride solution.

[0076] The nickel plate was immersed in a copper chloride mixed solution and placed in a hydrothermal reactor. The hydrothermal reactor was heated to 230°C and reacted for 780 minutes. The nano copper manganese particles adhered to the surface of the nickel plate. After cooling, the nickel plate was removed.

[0077] The nickel plate was placed in a tube furnace and heated to 213°C at a rate of 2°C / min under an argon atmosphere. The temperature was maintained for 490 min for vacuum carbonization, and then cooled to room temperature to prepare the modified nickel plate anode electrode 3.

[0078] In this embodiment, the peak current density of the nickel plate electrode is 42 mA / cm². 2 After modification, the peak current density of the modified nickel plate anode electrode 3 is 158 mA / cm². 2 The increased peak current density of the modified nickel plate anode can enhance the direct oxidation capacity of organic compounds and also improve the indirect oxidation capacity of hydroxyl radicals generated by hydrolysis.

[0079] In this embodiment, the modified titanium plate cathode electrode 4 is prepared according to the characteristics of coking wastewater, and its preparation method is as follows:

[0080] Select a titanium plate with a thickness of 1 mm, immerse it in a 3% hydrochloric acid solution for 45 minutes to remove surface metal oxides, rinse it with pure water 5 times after removal, immerse the titanium plate in petroleum ether for 35 minutes to remove surface organic matter, rinse it with pure water 5 times after removal, and then put the titanium plate into a vacuum drying oven.

[0081] To prepare a 978 mg / L manganese sulfate solution, add 26 mg of manganese chloride to each liter of manganese sulfate solution and sonicate for 35 min to form a mixed manganese sulfate solution.

[0082] The titanium plate was immersed in a manganese sulfate mixed solution for 490 min, and then placed in a muffle furnace. The muffle furnace was heated to 527°C at 8°C / min and held at that temperature for 75 min. The plate was then cooled to room temperature to prepare the modified titanium plate cathode electrode 4.

[0083] In this embodiment, the modified titanium plate cathode electrode 4 can reduce the occurrence of the anolyte oxygen evolution side reaction. This not only promotes the generation of hydroxyl ions that enhance oxidation, but also reduces electrode passivation, improves corrosion resistance, and thus increases the electrode's service life. In the coking nanofiltration concentrate, the standard potential of the unmodified titanium plate is +0.23V, while the standard potential of the modified titanium plate cathode electrode 4 is +0.11V, indicating that the modified titanium plate electrode has strong adhesion, good protection, and good corrosion resistance.

[0084] In this embodiment, the multi-media filter media 7 is composed of ceramsite, activated carbon, and water slag. The ceramsite is located in the lower layer of the multi-media filter 6. The ceramsite particles have a diameter of 300 mesh, a rough and hard surface, numerous micropores, and are grayish-black in color. The porosity of the ceramsite is 68%, and its density is 506 kg / m³. 3 It accounts for 10% of the total volume of the multi-media filter media 7. Activated carbon particles, with a particle size of 300 mesh and a specific surface area of ​​1360 m², are located in the middle layer of the multi-media filter 6. 2 / g, with an iodine value of 950mg / g, accounting for 50% of the total volume of the multi-media filter media 7. Water slag is located on the upper layer of the multi-media filter 6, with a particle size of 300 mesh. Water slag is a granular solid residue produced by water quenching of molten slag from the blast furnace during ironmaking. Its uniformity is 98%, accounting for 40% of the total volume of the multi-media filter media 7.

[0085] The coking nanofiltration concentrate enters the electrocatalytic oxidation unit 2 via a primary feed pump 1. Modified nickel plate anode electrode 3 and modified titanium plate cathode electrode 4 are placed on top of the electrocatalytic oxidation unit 2. Electrocatalytic oxidation directly generates hydroxide ions through electrolysis, which not only attack dissolved oxygen- or oxygen-free organic matter but also act on nitrogen-containing substances, leading to chain scission, oxidation, and even mineralization, generating CO2. During the electrocatalytic oxidation of the coking nanofiltration concentrate, Cl... - At the anode, the ammonia loses electrons and is oxidized, generating a large number of active chlorine and other free radicals, which can rapidly degrade ammonia nitrogen, causing relatively stable substances to react. During operation, the hydraulic residence time is 178 min, the distance between electrodes is 2 cm, and the current density is 6.3 A / m. 2 .

[0086] After electro-oxidation, the concentrate from coking nanofiltration has a conductivity of 35700 μS / cm, a sulfate ion concentration of 1452 mg / L, a COD concentration of 87 mg / L, and an ammonia nitrogen concentration of 6 mg / L.

[0087] Then, the coking nanofiltration concentrate is pumped into the multi-media filter 6 through the secondary inlet pump 5. The multi-media filter media 7 occupies 88% of the total volume of the multi-media filter 6, and the residence time of the coking nanofiltration concentrate in the multi-media filter 6 is 70 minutes.

[0088] The coking nanofiltration concentrate is discharged by the effluent pump 8 after passing through the multi-media filter 6. After treatment, the coking nanofiltration concentrate has a conductivity of 35700 μS / cm, a sulfate ion concentration of 1452 mg / L, a COD of 36 mg / L, and an ammonia nitrogen concentration of 4 mg / L.

[0089] Example 2

[0090] In this embodiment, the water quality characteristics of the coking nanofiltration concentrate are as follows: conductivity 21200 μS / cm, sulfate ion 1231 mg / L, COD 234 mg / L, and ammonia nitrogen 23 mg / L.

[0091] The modified nickel plate anode electrode 3 is prepared based on the characteristics of coking nanofiltration concentrate, and its preparation method is as follows:

[0092] Select a nickel plate with a thickness of 1 mm, immerse it in a sulfuric acid solution with a mass percentage of 4% for 34 minutes to remove surface metal oxides, rinse it three times with pure water after taking it out, immerse the nickel plate in methanol for 20 minutes to remove surface organic matter, rinse it three times with pure water after taking it out, and then put the nickel plate into a vacuum drying oven.

[0093] To prepare a 1.9 mol / L copper chloride solution, add 45 mg of manganese nitrate to each liter of copper chloride solution to form a mixed copper chloride solution.

[0094] The nickel plate was immersed in a copper chloride mixed solution and placed in a hydrothermal reactor. The hydrothermal reactor was heated to 170°C and reacted for 690 minutes. The nano copper manganese particles adhered to the surface of the nickel plate. After cooling, the nickel plate was removed.

[0095] A nickel plate was placed in a tube furnace and vacuum carbonized at 196°C at a rate of 4°C / min under an argon atmosphere for 345 min. It was then cooled to room temperature, successfully preparing the modified nickel plate anode electrode 3. The peak current density of the nickel plate electrode was 35 mA / cm². 2 After modification, the peak current density of the modified nickel plate anode electrode 3 is 151 mA / cm². 2 The increased peak current density of the modified nickel plate anode can enhance the direct oxidation capacity of organic compounds and also improve the indirect oxidation capacity of hydroxyl radicals generated by hydrolysis.

[0096] The modified titanium plate cathode electrode 4 is prepared according to the characteristics of coking wastewater, and its preparation method is as follows:

[0097] Select a titanium plate with a thickness of 1 mm, immerse it in a 1% hydrochloric acid solution for 41 min to remove surface metal oxides, rinse it three times with pure water after removal, immerse the titanium plate in petroleum ether for 26 min to remove surface organic matter, rinse it three times with pure water after removal, and then put the titanium plate into a vacuum drying oven.

[0098] To prepare a 459 mg / L manganese sulfate solution, add 21 mg of manganese chloride to each liter of manganese sulfate solution and sonicate for 20 min to form a mixed manganese sulfate solution.

[0099] The titanium plate was immersed in a manganese sulfate mixed solution for 450 min, and then placed in a muffle furnace. The muffle furnace was heated to 511℃ at 5℃ / min and held at that temperature for 65 min. The plate was then cooled to room temperature to prepare the modified titanium plate cathode electrode 4.

[0100] In this embodiment, the modified titanium plate cathode electrode 4 can reduce the occurrence of the anolyte oxygen evolution side reaction. This not only promotes the generation of hydroxyl ions that enhance oxidation, but also reduces electrode passivation, improves corrosion resistance, and thus increases the electrode's service life. In the coking nanofiltration concentrate, the standard potential of the unmodified titanium plate is +0.23V, while the standard potential of the modified titanium plate cathode electrode 4 is +0.11V, indicating that the modified titanium plate electrode has strong adhesion, good protection, and good corrosion resistance.

[0101] In this embodiment, the multi-media filter media 7 is composed of ceramsite, activated carbon, and water slag. The ceramsite is located in the lower layer of the multi-media filter 6. The ceramsite particles have a diameter of 200 mesh, a rough and hard surface, numerous micropores, and are grayish-black in color. The porosity of the ceramsite is 66%, and its density is 502 kg / m³. 3 It accounts for 10% of the total volume of the multi-media filter media 7. Activated carbon particles are located in the middle layer of the multi-media filter 6, with a particle size of 200 mesh and a specific surface area of ​​1250 m². 2 / g, with an iodine value of 800mg / g, accounting for 50% of the total volume of the multi-media filter media. Water slag is located on the upper layer of the multi-media filter 6, with a particle size of 200 mesh. Water slag is a granular solid residue produced by water quenching of molten slag from the blast furnace during ironmaking. Its uniformity is 85%, accounting for 40% of the total volume of the multi-media filter media 7.

[0102] The coking nanofiltration concentrate enters the electrocatalytic oxidation unit 2 via a primary feed pump 1. Modified nickel plate anode electrode 3 and modified titanium plate cathode electrode 4 are placed on top of the electrocatalytic oxidation unit 2. Electrocatalytic oxidation directly generates hydroxide ions through electrolysis, which not only attack dissolved oxygen- or oxygen-free organic matter but also act on nitrogen-containing substances, leading to chain scission, oxidation, and even mineralization, generating CO2. During the electrocatalytic oxidation of the coking nanofiltration concentrate, Cl... - At the anode, the ammonia loses electrons and is oxidized, generating a large number of active chlorine and other free radicals, which can rapidly degrade ammonia nitrogen, causing relatively stable substances to react. During operation, the hydraulic residence time is 123 min, the distance between electrodes is 2.5 cm, and the current density is 5.1 A / m. 2 .

[0103] After electro-oxidation, the concentrated coking nanofiltration water has a conductivity of 21200 μS / cm, a sulfate ion concentration of 1231 mg / L, a COD concentration of 66 mg / L, and an ammonia nitrogen concentration of 3 mg / L.

[0104] Then, the coking nanofiltration concentrate is pumped into the multi-media filter 6 through the secondary inlet pump 5. The multi-media filter media 7 occupies 80% of the total volume of the multi-media filter 6, and the residence time of the coking nanofiltration concentrate in the multi-media filter 6 is 45 minutes.

[0105] The coking nanofiltration concentrate is filtered through multi-media filter 6 and then discharged by effluent pump 8. After treatment, the coking nanofiltration concentrate has a conductivity of 21200 μS / cm, a sulfate ion concentration of 1231 mg / L, a COD of 29 mg / L, and an ammonia nitrogen concentration of 2 mg / L.

[0106] Example 3

[0107] In this embodiment, the water quality characteristics of the coking nanofiltration concentrate are as follows: conductivity 28700 μS / cm, sulfate ion 1351 mg / L, COD 298 mg / L, and ammonia nitrogen 29 mg / L.

[0108] The modified nickel plate anode electrode 3 is prepared based on the characteristics of coking nanofiltration concentrate, and its preparation method is as follows:

[0109] Select a nickel plate with a thickness of 1 mm, immerse it in a sulfuric acid solution with a mass percentage of 6% for 36 minutes to remove surface metal oxides, rinse it with pure water 4 times after taking it out, immerse the nickel plate in methanol for 23 minutes to remove surface organic matter, rinse it with pure water 4 times after taking it out, and then put the nickel plate into a vacuum drying oven.

[0110] To prepare a 2.5 mol / L copper chloride solution, add 51 mg of manganese nitrate to each liter of copper chloride solution to form a mixed copper chloride solution.

[0111] The nickel plate was immersed in a copper chloride mixed solution and placed in a hydrothermal reactor. The hydrothermal reactor was heated to 199°C and reacted for 735 minutes. The nano copper manganese particles adhered to the surface of the nickel plate. After cooling, the nickel plate was removed.

[0112] The nickel plate was placed in a tube furnace and heated to 206°C at a rate of 3°C / min under an argon atmosphere. The temperature was maintained for 403 min for vacuum carbonization, and then cooled to room temperature to prepare the modified nickel plate anode electrode 3.

[0113] In this embodiment, the peak current density of the nickel plate electrode is 39 mA / cm². 2 After modification, the peak current density of the modified nickel plate anode electrode 3 is 154 mA / cm². 2The increased peak current density of the modified nickel plate anode can enhance the direct oxidation capacity of organic compounds and also improve the indirect oxidation capacity of hydroxyl radicals generated by hydrolysis.

[0114] The modified titanium plate cathode electrode 4 is prepared according to the characteristics of coking wastewater, and its preparation method is as follows:

[0115] Select a titanium plate with a thickness of 1 mm, immerse it in a 2% hydrochloric acid solution for 43 minutes to remove surface metal oxides, rinse it with pure water 4 times after removal, immerse the titanium plate in petroleum ether for 31 minutes to remove surface organic matter, rinse it with pure water 4 times after removal, and then put the titanium plate into a vacuum drying oven.

[0116] To prepare a 672 mg / L manganese sulfate solution, add 23 mg of manganese chloride to each liter of manganese sulfate solution and sonicate for 28 min to form a mixed manganese sulfate solution.

[0117] The titanium plate was immersed in a manganese sulfate mixed solution for 471 min, then placed in a muffle furnace, and the muffle furnace was heated to 518℃ at 6℃ / min, held at that temperature for 69 min, and then cooled to room temperature to prepare the modified titanium plate cathode electrode 4.

[0118] The modified titanium plate cathode electrode 4 can reduce the occurrence of the anolyte oxygen evolution side reaction. This not only promotes the generation of hydroxyl ions, which enhance oxidation, but also reduces electrode passivation and improves corrosion resistance, thereby increasing the electrode's service life. In coking nanofiltration concentrate, the standard potential of the unmodified titanium plate is +0.23V, while the standard potential of the modified titanium plate cathode electrode 4 is +0.11V, indicating that the modified titanium plate electrode has strong adhesion, good protection, and good corrosion resistance.

[0119] In this embodiment, the multi-media filter media 7 is composed of ceramsite, activated carbon, and water slag. The ceramsite is located in the lower layer of the multi-media filter 6. The ceramsite particles have a diameter of 200 mesh, a rough and hard surface, numerous micropores, and are grayish-black in color. The porosity of the ceramsite is 67%, and its density is 505 kg / m³. 3 It accounts for 10% of the total volume of the multi-media filter media 7. Activated carbon particles are located in the middle layer of the multi-media filter 6, with a particle size of 200 mesh and a specific surface area of ​​1298 m². 2 / g, with an iodine value of 900mg / g, accounting for 50% of the total volume of the multi-media filter media 7. Water slag is located on the upper layer of the multi-media filter 6, with a particle size of 200 mesh. Water slag is a granular solid residue produced by water quenching of molten slag from the blast furnace during ironmaking. Its uniformity is 91%, accounting for 40% of the total volume of the multi-media filter media 7.

[0120] The coking nanofiltration concentrate enters the electrocatalytic oxidation unit 2 via a primary feed pump 1. Modified nickel plate anode electrode 3 and modified titanium plate cathode electrode 4 are placed on top of the electrocatalytic oxidation unit 2. Electrocatalytic oxidation directly generates hydroxide ions through electrolysis, which not only attack dissolved oxygen- or oxygen-free organic matter but also act on nitrogen-containing substances, leading to chain scission, oxidation, and even mineralization, generating CO2. During the electrocatalytic oxidation of the coking nanofiltration concentrate, Cl... - At the anode, the ammonia loses electrons and is oxidized, generating a large number of active chlorine and other free radicals, which can rapidly degrade ammonia nitrogen, causing relatively stable substances to react. During operation, the hydraulic residence time is 166 min, the distance between electrodes is 2 cm, and the current density is 5.8 A / m. 2 .

[0121] After electro-oxidation, the concentrated coking nanofiltration water has a conductivity of 28700 μS / cm, a sulfate ion concentration of 1351 mg / L, a COD concentration of 73 mg / L, and an ammonia nitrogen concentration of 5 mg / L.

[0122] Then, the coking nanofiltration concentrate is pumped into the multi-media filter 6 via the secondary inlet pump 5. The multi-media filter media 7 occupies 83% of the total volume of the multi-media filter 6, and the residence time of the coking nanofiltration concentrate in the multi-media filter 6 is 63 minutes.

[0123] The coking nanofiltration concentrate is discharged by the effluent pump 8 after passing through the multi-media filter 6. After treatment, the coking nanofiltration concentrate has a conductivity of 28700 μS / cm, a sulfate ion concentration of 1351 mg / L, a COD of 32 mg / L, and an ammonia nitrogen concentration of 3 mg / L.

[0124] As can be seen, the coking nanofiltration concentrate treatment method and system provided in this embodiment of the invention achieves the standard discharge of coking nanofiltration concentrate. The entire process has low initial investment, stable treatment effect and low production and operation cost, fully demonstrating the effect of energy saving and emission reduction. It is an environmentally friendly green steel production process.

[0125] In summary, the embodiments of the present invention provide a method and system for treating coking nanofiltration concentrate, which first treats the coking nanofiltration concentrate by electrocatalytic oxidation, Cl -The anode loses electrons and is oxidized, generating a large number of active chlorine and other free radicals, which can rapidly degrade ammonia nitrogen. This allows relatively stable substances to react, and then the solution is filtered by a multi-media filter 6, which can economically and efficiently remove COD and ammonia nitrogen from the coking nanofiltration concentrate. Furthermore, the modified nickel plate has an increased peak current density, which can improve the direct oxidation ability of organic compounds and the indirect oxidation ability of hydroxyl free radicals generated by hydrolysis. The modified titanium plate cathode electrode 4 can reduce the occurrence of oxygen evolution side reactions at the anode, which not only promotes the generation of hydroxide ions that enhance oxidation, but also reduces electrode passivation, improves corrosion resistance, and thus increases the service life of the electrode.

[0126] Furthermore, it should be understood that although the present invention has been disclosed above with reference to preferred embodiments, these embodiments are not intended to limit the present invention. For any person skilled in the art, many possible variations and modifications can be made to the technical solutions of the present invention based on the disclosed technical content, or equivalent embodiments can be modified accordingly, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention shall still fall within the scope of protection of the present invention.

Claims

1. A method for treating coking nanofiltration concentrate, characterized in that, include: Modified nickel plate anode electrode, modified titanium plate cathode electrode, and multi-media filter media were pre-configured to meet the water quality characteristics of coking nanofiltration concentrate. The coking nanofiltration concentrate is fed into an electrocatalytic oxidation device for treatment. The electrocatalytic oxidation device uses the modified nickel plate anode electrode as the anode electrode and the modified titanium plate cathode electrode as the cathode electrode. The effluent from the electrocatalytic oxidation device is fed into a multi-media filter for filtration, and the multi-media filter contains the multi-media filter media. The method for preparing the modified nickel plate anode electrode includes: Select a nickel plate with a thickness of 1 mm, immerse it in a sulfuric acid solution with a mass percentage of 4-7% for 34-39 minutes to remove surface metal oxides, rinse it with pure water 3-5 times after removal, immerse the nickel plate in methanol for 20-25 minutes to remove surface organic matter, rinse it with pure water 3-5 times after removal, and then put the nickel plate into a vacuum drying oven. Prepare a 1.9-3.8 mol / L copper chloride solution by adding 45-56 mg of manganese nitrate to each liter of the copper chloride solution to form a mixed copper chloride solution; The nickel plate is immersed in the copper chloride mixed solution, placed in a hydrothermal reactor, heated to 170~230℃, reacted for 690~780 min, and then cooled and removed. The nickel plate was placed in a tube furnace and heated to 196-213°C at a rate of 2-4°C / min under an argon atmosphere. The temperature was maintained for 345-490 min for vacuum carbonization, and then cooled to room temperature to obtain the modified nickel plate anode electrode. The method for preparing the modified titanium plate cathode electrode includes: Select a titanium plate with a thickness of 1 mm, immerse it in a hydrochloric acid solution with a mass percentage of 1-3% for 41-45 minutes to remove surface metal oxides, rinse it with pure water 3-5 times after removal, immerse the titanium plate in petroleum ether for 26-35 minutes to remove surface organic matter, rinse it with pure water 3-5 times after removal, and then put the titanium plate into a vacuum drying oven. Prepare a manganese sulfate solution with a concentration of 459-978 mg / L by adding 21-26 mg of manganese chloride to each liter of the manganese sulfate solution and sonicating for 20-35 min to form a manganese sulfate mixed solution. The titanium plate is immersed in the manganese sulfate mixed solution for 450-490 min, then placed in a muffle furnace, and the temperature of the muffle furnace is increased to 511-527℃ at 5-8℃ / min, held at the temperature for 65-75 min, and then cooled to room temperature to prepare the modified titanium plate cathode electrode.

2. The coking nanofiltration concentrate treatment method according to claim 1, characterized in that, The distance between the modified nickel plate anode electrode and the modified titanium plate cathode electrode is 2~2.5 cm, and the current density is 5.1~6.3 A / cm. .

3. The coking nanofiltration concentrate treatment method according to claim 1, characterized in that, The multi-media filter media consists of ceramsite, activated carbon particles, and water sludge. The ceramsite is placed in the lower layer of the multi-media filter, the activated carbon particles are placed in the middle layer of the multi-media filter, and the water sludge is placed in the upper layer of the multi-media filter.

4. The coking nanofiltration concentrate treatment method according to claim 3, characterized in that, The ceramsite has a porosity of 66-68% and a density of 502-506 kg / m³. It accounts for 10% of the total volume of the multi-media filter media.

5. The coking nanofiltration concentrate treatment method according to claim 3, characterized in that, The activated carbon particles have a particle size of 200-300 mesh and a specific surface area of ​​1250-1360. / g, with an iodine value of 800~950 mg / g, accounting for 50% of the total volume of the multi-media filter media.

6. The coking nanofiltration concentrate treatment method according to claim 3, characterized in that, The slag has a particle size of 200-300 mesh. The slag is a granular solid residue produced by water quenching of molten slag from the blast furnace during ironmaking. The uniformity is 85%-98%, accounting for 40% of the total volume of the multi-media filter material.

7. The coking nanofiltration concentrate treatment method according to claim 1, characterized in that, The hydraulic residence time of the coking nanofiltration concentrate in the electrocatalytic oxidation device is 123~178 min, and the hydraulic residence time of the coking nanofiltration concentrate in the multi-media filter is 45~70 min.

8. A coking nanofiltration concentrate treatment system for implementing the coking nanofiltration concentrate treatment method according to any one of claims 1-7, characterized in that, Includes a drug dispensing unit, an electrocatalytic oxidation device, and a multi-media filter; The dosing unit is used to pre-configure modified nickel plate anode electrode, modified titanium plate cathode electrode, and multi-media filter media according to the water quality characteristics of coking nanofiltration concentrate. The electrocatalytic oxidation device is used to electrocatalytically oxidize the coking nanofiltration concentrate. The electrocatalytic oxidation device uses the modified nickel plate anode electrode as the anode electrode and the modified titanium plate cathode electrode as the cathode electrode. The multi-media filter is used to filter the effluent from the electrocatalytic oxidation device, and the multi-media filter contains the multi-media filter media.

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