An electrochemical oxidation device and its treatment system for treating ammonia nitrogen wastewater.

Abstract

This invention provides an electrochemical oxidation device for treating ammonia nitrogen wastewater. The device includes a shell divided into a gas-liquid mixing chamber and a reaction chamber by a partition plate. The gas-liquid mixing chamber has an air inlet, a liquid inlet, and an air outlet. Inside, from top to bottom, are a spray section, a first packing layer, and an air jet section for mixing ammonia gas after stripping from the ammonia nitrogen wastewater with the electrolyte. The reaction chamber has a liquid outlet and a drain outlet, and contains the electrolyte with staggered first and second electrodes arranged inside. The liquid outlet and inlet are connected by a circulation pipeline, on which a pump drives the electrolyte circulation. The spray section receives the electrolyte and sprays it onto the first packing layer, while the air jet section sprays ammonia gas onto the packing layer, achieving sufficient gas-liquid contact. The device uses non-contact electrochemical oxidation to convert ammonia gas into nitrogen gas, effectively treating ammonia nitrogen wastewater. This invention also provides a treatment system utilizing the above-mentioned electrochemical oxidation device.

Description

Technical Field

[0001] This utility model relates to the field of ammonia nitrogen wastewater treatment technology, specifically to an electrochemical oxidation device and its treatment system for treating ammonia nitrogen wastewater. Background Technology

[0002] Ammonia nitrogen wastewater has a wide range of sources. Industrial production such as petrochemicals and fertilizer manufacturing, as well as agricultural activities and domestic sewage discharge, all lead to large amounts of ammonia nitrogen entering the environment. Ammonia nitrogen in wastewater mainly exists as free ammonia (NH3) and ammonium ions (NH4+). + It exists in the form of ammonia nitrogen, and the concentration of ammonia nitrogen in wastewater varies greatly from industry to industry. It has a complex composition and contains high concentrations of salt, heavy metal ions and organic pollutants.

[0003] Among ammonia nitrogen pollution control technologies, electrochemical ammonia nitrogen oxidation technology has attracted widespread attention due to its advantages of zero reagent addition and harmless decomposition, as it can directly decompose pollutants into nitrogen gas (N2) through electrode reactions. However, in traditional applications, this technology is significantly constrained by the complex matrix of the wastewater: the wastewater is in direct contact with the electrode assembly, and the Ca in the wastewater... 2+ Mg 2+ Scale buildup at the cathode leads to the reduction and deposition of metal ions, causing electrode performance degradation and shortened lifespan. Organic pollutants compete with ammonia nitrogen for anodic oxidation materials, reducing the efficiency of ammonia nitrogen oxidation current. Insufficient conductivity in some wastewater results in a significant increase in treatment energy consumption and accelerates anodic corrosion. Chloride-containing wastewater may also produce toxic byproducts such as chlorinated organic compounds. Current technologies struggle to achieve harmless decomposition capabilities that are compatible with the general application to complex water qualities. Therefore, developing a novel electrochemical device to completely oxidize ammonia gas from ammonia nitrogen wastewater after stripping, while simultaneously preventing direct contact between the wastewater and the electrode assembly, is a pressing issue that needs to be addressed. Utility Model Content

[0004] To address the problems existing in the prior art, the first objective of this utility model is to provide an electrochemical oxidation device for treating ammonia nitrogen wastewater. The electrochemical oxidation device receives ammonia gas after stripping from the ammonia nitrogen wastewater and adopts a non-contact electrochemical oxidation process. The stripped ammonia gas is directly converted into harmless nitrogen gas for emission, thereby achieving efficient removal and complete harmless decomposition of ammonia nitrogen in the wastewater.

[0005] The second objective of this invention is to provide a processing system utilizing the aforementioned electrochemical oxidation device.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An electrochemical oxidation device for treating ammonia nitrogen wastewater includes: a vertically arranged shell having a partition plate to divide the space inside the shell into a gas-liquid mixing chamber and a reaction chamber arranged vertically, the partition plate having multiple through holes; the gas-liquid mixing chamber includes an air inlet on one side for receiving ammonia gas from the ammonia nitrogen wastewater after stripping, a liquid inlet on the other side, and an air outlet on the top, with the liquid inlet located above the air inlet; the gas-liquid mixing chamber has a spray section, a first packing layer, and an air jet section arranged sequentially from top to bottom; the reaction chamber includes a liquid outlet and a drain outlet on one side, the liquid outlet being connected to the liquid inlet via a circulation pipeline, and contains an electrolyte, and has multiple first and second electrodes immersed below the liquid level; wherein the spray section is connected to the liquid inlet for receiving the electrolyte in the reaction chamber and spraying it onto the first packing layer, and the air jet section is connected to the air inlet for spraying the ammonia gas onto the first packing layer.

[0008] According to one example, the first electrode and the second electrode are arranged alternately, and the first electrode and the second electrode are electrically connected to the positive and negative terminals of an external power source, respectively.

[0009] According to one example, the first electrode is a ruthenium-iridium titanium-based coated electrode plate, and the second electrode is a pure titanium plate.

[0010] According to one example, a second filler layer is also provided above the spray section.

[0011] According to one example, the electrolyte is a 2M sodium chloride electrolyte.

[0012] According to one example, a pump body is configured on the pipeline between the outlet and the inlet.

[0013] According to one example, the spray section includes a first pipe connected to the liquid inlet, the first pipe extending horizontally in the gas-liquid mixing chamber, and a plurality of spray nozzles disposed at the lower part of the first pipe facing the first packing layer; the air jet section includes a second pipe connected to the air inlet, the second pipe extending horizontally in the gas-liquid mixing chamber, and a plurality of air jet nozzles disposed at the upper part of the second pipe facing the first packing layer.

[0014] According to one example, the side of the reaction chamber is provided with an installation port and a cover plate rotatably disposed on the installation port. A plurality of first electrodes are spaced apart on the inner side of the cover plate. When the cover plate and the installation port are sealed and overlapped, the first electrodes and the second electrodes are arranged in an alternating manner.

[0015] According to one example, both the first packing layer and the second packing layer are Pall ring packings.

[0016] A treatment system for treating ammonia nitrogen wastewater includes: a pH adjusting tank, the pH adjusting tank including a first inlet formed on one side for receiving ammonia nitrogen wastewater and a second inlet formed on the other side for discharging alkaline ammonia nitrogen wastewater; a stripping tower, the stripping tower including a third inlet formed on one side for receiving the alkaline ammonia nitrogen wastewater and a jet outlet formed on the other side for receiving gas, and an exhaust outlet formed at the top for discharging ammonia gas, wherein a heater for heating the alkaline ammonia nitrogen wastewater is disposed inside; and the aforementioned electrochemical oxidation device, wherein the gas inlet is connected to the exhaust outlet via a pipeline.

[0017] This utility model has the following advantages:

[0018] This invention relates to an electrochemical oxidation device that achieves efficient mass transfer through a vertically arranged gas-liquid mixing chamber and a reaction chamber. Within the gas-liquid mixing chamber, a spray section, a first packing layer, and a jetting section are arranged from top to bottom. The liquid inlet is higher than the gas inlet to create counter-current flow between the electrolyte and ammonia, which, combined with the packing layer, increases the gas-liquid contact area. The spray section uniformly sprays the electrolyte through a first pipe and a spray head, while the jetting section sprays ammonia upwards through a second pipe and a jetting head. Both components form an enhanced mass transfer zone within the first packing layer, effectively promoting the absorption and dissociation of ammonia. Within the reaction chamber, ruthenium-iridium-titanium coated electrode plates and pure titanium plates are alternately arranged to create an optimized electric field. The ruthenium-iridium-titanium coating exhibits good chlorine evolution catalytic activity in 2M sodium chloride electrolyte, efficiently generating strong oxidizing substances such as hypochlorite ions, rapidly oxidizing ammonia to nitrogen. In practical applications, by optimizing process conditions, this invention enables continuous wastewater treatment with an ammonia nitrogen removal rate greater than 99%, reducing the ammonia nitrogen concentration to below 100 mg / L, and a nitrogen conversion rate greater than 90%, reaching 100% under certain operating conditions. This lays a solid foundation for subsequent wastewater treatment and recycling. The rotatable flap structure on the side of the reaction chamber allows for electrode installation and replacement without disassembling the entire machine. The circulation pipeline between the inlet and outlet, in conjunction with the pump, ensures continuous electrolyte circulation, maintaining a stable concentration of oxidizing substances in the gas-liquid mixing chamber and preventing current efficiency degradation caused by high concentrations of organic pollutants. Attached Figure Description

[0019] Figure 1 This is a three-dimensional structural schematic diagram of the electrochemical oxidation device of this utility model.

[0020] Figure 2 This is a three-dimensional structural schematic diagram of the electrochemical oxidation device of this utility model from another angle.

[0021] Figure 3 This is a three-dimensional structural diagram of the electrochemical oxidation device of this utility model, showing the reaction chamber opened through a cover plate.

[0022] Figure 4 This is a three-dimensional sectional view of the electrochemical oxidation device of this utility model.

[0023] Figure 5 This is a three-dimensional structural diagram of the reaction chamber of this utility model.

[0024] Wherein, 1 is the shell, 101 is the gas-liquid mixing chamber, 101a is the air inlet, 101b is the liquid inlet, 101c is the air outlet, 101c1 is the grille, 101d is the partition plate, 101d1 is the connecting port, 102 is the spray section, 102a is the first pipe body, 102b is the liquid spray head, 103 is the first packing layer, 103a is the first orifice plate, 103b is the first Pall ring, 104 is the jet section, 104a is the second pipe body, 1 04b is the jet head, 105 is the second packing layer, 105a is the second orifice plate, 105b is the second Pall ring, 106 is the reaction chamber, 106a is the liquid outlet, 106b is the liquid drain outlet, 106c is the circulation pipeline, 106d is the pump body, 106e is the mounting port, 106f is the limiting block, 106g is the branch pipe, 107 is the first electrode, 108 is the second electrode, 108a is the groove, 109 is the cover plate, and 109a is the handle. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0026] Reference Figure 1-4 The invention illustrates an embodiment of an electrochemical oxidation device for treating ammonia nitrogen wastewater. The device mainly includes a shell 1 and a gas-liquid mixing chamber 101 and a reaction chamber 106 formed inside the shell 1. It adopts a non-contact electrochemical oxidation process, in which the ammonia gas stripped off is directly converted into harmless nitrogen gas for emission, avoiding pollution caused by direct contact between the electrodes and complex wastewater, and achieving efficient and harmless treatment of ammonia nitrogen.

[0027] Reference Figure 1 and Figure 4 The shell 1 is vertically arranged and has a vertical cuboid structure, but it can also be cylindrical, polygonal, or other structures. The shell 1 has a partition plate 101d to divide the space inside the shell 1 into a gas-liquid mixing chamber 101 and a reaction chamber 106 arranged vertically. Multiple through holes are formed on the partition plate 101d, and the gas-liquid mixing chamber 101 and the reaction chamber 106 can achieve electrolyte circulation through multiple connecting ports 101d1 on the partition plate 101d.

[0028] Reference Figure 4The gas-liquid mixing chamber 101 is mainly used for ammonia absorption and oxidation reactions. It includes an air inlet 101a on one side for receiving ammonia from the stripped ammonia nitrogen wastewater, a liquid inlet 101b on the other side, and an air outlet 101c at the top, with the liquid inlet 101b located above the air inlet 101a. From top to bottom, the gas-liquid mixing chamber 101 is equipped with a spray section 102, a first packing layer 103, and a jet spray section 104. The jet spray section 104 is connected to the air inlet 101a and sprays ammonia onto the first packing layer 103. The spray section 102 is connected to the liquid inlet 101b and receives the electrolyte from the reaction chamber 106, spraying it onto the first packing layer 103. A second packing layer 105 is also provided above the spray section 102 to prevent water vapor from escaping through the air outlet 101c. Both the first packing layer 103 and the second packing layer 105 are Pall ring packing.

[0029] Continue to refer to Figure 4 The jetting section 104 includes a second pipe 104a connected to the air inlet 101a. The second pipe 104a extends horizontally within the gas-liquid mixing chamber 101. Multiple jet nozzles 104b are disposed on the upper part of the second pipe 104a and face the first packing layer 103. One end of the second pipe 104a is connected to the air inlet 101a on the side wall of the housing 1 to receive ammonia gas after stripping from the ammonia nitrogen wastewater. The other end extends horizontally within the housing 1 with the jetting direction upwards. The spraying section 102 includes a first pipe 102a connected to the liquid inlet 101b. The first pipe 102a extends horizontally within the gas-liquid mixing chamber 101. Multiple liquid spray nozzles 102b are disposed on the lower part of the first pipe 102a and face the first packing layer 103. One end of the first tube 102a is connected to the inlet 101b and is connected to the outlet 106a of the reaction chamber 106 through the circulation pipe 106c. The other end extends horizontally and the spray direction is downward. The first tube 102a and the second tube 104a are arranged in a countercurrent manner.

[0030] The first packing layer 103 is located between the first tube body 102a and the second tube body 104a to increase the gas-liquid contact area. It includes two square first perforated plates 103a arranged vertically, with all four sides fixed to the inner wall of the housing 1. Multiple first Pall rings 103b are accommodated between the two first perforated plates 103a. A second packing layer 105 is disposed above the first tube body 102a. The second packing layer 105 includes a second perforated plate 105a, and multiple second Pall rings 105b are accommodated between the second perforated plate 105a and the top wall of the housing 1. A grid 101c1 is provided at the gas outlet 101c to block the second Pall rings 105b. The shapes of the first Pall rings 103b and the second Pall rings 105b can be spherical, polygonal, cylindrical, etc.

[0031] Reference Figure 4 and Figure 5The reaction chamber 106 includes an outlet 106a and a drain 106b formed on one side. The outlet 106a is connected to the inlet 101b via a circulation pipe 106c. It contains electrolyte and is equipped with multiple first electrodes 107 and second electrodes 108 submerged below the liquid level. A pump body 106d is installed on the pipe between the outlet 106a and the inlet 101b to lift the electrolyte to the first tube 102a and distribute it evenly to the first packing layer 103. The electrolyte is a sodium chloride electrolyte with a concentration of 1-3M, preferably 2M. The first electrode 107 and the second electrode 108 are arranged alternately, and the first electrode 107 and the second electrode 108 are electrically connected to the positive and negative terminals of an external power source, respectively, to form an electric field for electrolyzing the electrolyte. The first electrode 107 is a ruthenium-iridium titanium-based coated electrode plate, and multiple first electrodes 107 are electrically connected. The second electrode 108 is a pure titanium plate, and multiple second electrodes 108 are electrically connected. By applying a 10 mA / cm² pressure to the first electrode 107 and the second electrode 108... 2 -30mA / cm 2 Under constant current direct current, the electrolyte undergoes an electrochemical reaction, generating an electrolyte containing hypochlorous acid and chlorine free radicals.

[0032] A mounting port 106e is provided on the side of the reaction chamber 106. A cover plate 109 is rotatably mounted at the mounting port 106e. Multiple first electrodes 107 are spaced apart on the inner side of the cover plate 109. When the cover plate 109 and the mounting port 106e are sealed and overlapped, the first electrodes 107 are embedded into the reaction chamber 106 as the cover plate 109 rotates, and are located between two second electrodes 108, so that the first electrodes 107 and the second electrodes 108 are arranged in an alternating manner. This flip-plate structure facilitates the disassembly and maintenance of the electrodes. A handle 109a is provided on the outer side of the cover plate 109 to facilitate the operator to open or close the cover plate 109. Multiple second electrodes 108 are spaced apart along the length of the reaction chamber 106, and their lower parts are engaged with multiple limiting blocks 106f located at the bottom of the reaction chamber 106. In addition, the liquid outlet 106a and the liquid drain outlet 106b are both located on the side of the reaction chamber 106. A branch pipe 106g extending horizontally to the middle of the reaction chamber 106 is provided at the liquid outlet 106a for receiving electrolyte. A groove 108a is formed at the bottom of the second electrode 108 so that the branch pipe 106g can pass through.

[0033] In this process, ammonia gas stripped from ammonia nitrogen wastewater enters the gas-liquid mixing chamber 101 through inlet 101a and diffuses evenly upwards through the second pipe 104a to the first packing layer 103. Simultaneously, the electrolyte containing hypochlorous acid and chlorine free radicals generated in reaction chamber 106 is pumped to the first pipe 102a by an external pump 106d and evenly distributed into the first packing layer 103. Within the first packing layer 103, ammonia gas and electrolyte undergo countercurrent mixing and contact. After being absorbed, the ammonia gas reacts rapidly with the hypochlorous acid and chlorine free radicals in the electrolyte to form nitrogen gas. The generated nitrogen gas passes through the second packing layer 105 and is discharged from the outlet 101c at the top of the gas-liquid mixing chamber 101, ultimately being drawn into the external environment by a fan. The electrolyte after the reaction flows back to the reaction chamber 106 through the connecting port 101d1 on the partition plate 101d to continue participating in the electrochemical reaction, forming a cycle treatment process to achieve efficient and harmless decomposition of ammonia. Moreover, ammonia does not come into direct contact with the first electrode 107 or the second electrode 108 throughout the process, which truly solves the fundamental problem of interference of complex water quality on the electrochemical process.

[0034] In an embodiment not shown, the treatment system utilizing the aforementioned electrochemical oxidation device mainly includes a pH adjustment tank, a stripping tower, and an electrochemical oxidation device connected in sequence. The pH adjustment tank is used to receive and adjust the pH value of ammonia nitrogen wastewater to 11-13. The pH adjustment tank includes a first inlet formed on one side for receiving ammonia nitrogen wastewater and a second inlet formed on the other side for receiving alkaline reagents, and an outlet 106a formed on the other side for discharging alkaline ammonia nitrogen wastewater. A stirrer and a pH monitor are configured on the top of the pH adjustment tank. The stirrer is used to mix the ammonia nitrogen wastewater with the alkaline reagents to bring the wastewater to a predetermined pH value, and the pH monitor is used to monitor the pH of the wastewater in real time.

[0035] The stripping tower heats ammonia nitrogen wastewater from the pH adjustment tank and introduces gas, converting free ammonia nitrogen in the wastewater into ammonia gas, which is then separated and discharged. It includes a third inlet on one side for receiving alkaline ammonia nitrogen wastewater and a jet outlet for receiving gas, as well as an exhaust outlet on the upper part for discharging ammonia gas. An internal heater is installed for heating the alkaline ammonia nitrogen wastewater. The gas inlet 101a of the electrochemical oxidation unit is connected to the exhaust outlet via a pipeline. Ammonia gas discharged from the stripping tower enters the gas-liquid mixing chamber 101 through the gas inlet 101a on the side wall of the shell 1.

[0036] In an embodiment not shown, the stripping tower has stripping zones and a heating zone arranged vertically. Within the stripping zone, a jet pipe is located at the bottom with the jet direction upwards, and a spray pipe is located at the top with the spray direction downwards, thus forming a counter-current arrangement. A packing layer is placed between the jet pipe and the spray pipe, and another packing layer is placed above the spray pipe. Both packing layers are made of PP Pall ring packing to increase the gas-liquid contact area and ensure more thorough gas-liquid mixing. The heating zone receives alkaline wastewater from a pH adjustment tank through a third inlet. The heater, located within the heating zone and below the liquid level, is a constant-temperature heater that heats the wastewater to a constant temperature, for example, 20-40°C. The heated wastewater is then pumped by an external pump to the spray pipe at the top of the stripping zone, where it is evenly sprayed onto the packing layer below through multiple nozzles. At this time, air or steam is introduced into the jet pipe and comes into countercurrent contact with the falling wastewater in the packing layer, causing the free ammonia nitrogen to volatilize into ammonia gas. The ammonia gas carries a small amount of water vapor and rises through the packing layer above the spray pipe to intercept the droplets, causing the water vapor to condense on the surface of the packing, while the remaining dry gas is discharged from the exhaust port at the top.

[0037] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention should be considered equivalent substitutions and are included within the protection scope of the present invention. The embodiments described in this disclosure are intended as non-limiting examples, and other embodiments may take various and alternative forms. Furthermore, the drawings are not necessarily to scale and may present simplified expressions of various features of the present disclosure, including, for example, specific dimensions, orientations, positions, and shapes. Details associated with such features will be determined in part by the intended application and usage environment of the described embodiments.

[0038] The detailed description and accompanying drawings are supporting and descriptive of this teaching, but the scope of this teaching is defined only by the claims. While the best mode and some other embodiments for carrying out this teaching have been described in detail, various alternative designs and embodiments exist for practicing the teaching as defined in the appended claims. Furthermore, this disclosure expressly includes combinations and sub-combinations of the elements and features set forth above and below.

Claims

1. An electrochemical oxidation device for treating ammonia nitrogen wastewater, characterized in that, include: A vertically arranged shell, the shell having a partition plate to divide the space inside the shell into a gas-liquid mixing chamber and a reaction chamber arranged vertically, the partition plate having a plurality of through holes; The gas-liquid mixing chamber includes an air inlet formed on one side for receiving ammonia gas from the stripped ammonia nitrogen wastewater, a liquid inlet formed on the other side, and an air outlet formed at the top, with the liquid inlet located above the air inlet. The gas-liquid mixing chamber is provided with a spray section, a first packing layer, and an air jet section in sequence from top to bottom. The reaction chamber includes an outlet and a drain on one side. The outlet is connected to the inlet via a circulation pipe. The chamber contains electrolyte and is equipped with multiple first and second electrodes submerged below the liquid level. The spray section is connected to the liquid inlet and is used to receive the electrolyte in the reaction chamber and spray it onto the first packing layer. The jet section is connected to the air inlet and is used to spray the ammonia gas onto the first packing layer.

2. The electrochemical oxidation device according to claim 1, characterized in that, The first electrode and the second electrode are arranged alternately, and the first electrode and the second electrode are electrically connected to the positive and negative terminals of the external power supply, respectively.

3. The electrochemical oxidation device according to claim 1, characterized in that, The first electrode is a ruthenium-iridium titanium-based coated electrode plate, and the second electrode is a pure titanium plate.

4. The electrochemical oxidation device according to claim 1, characterized in that, A second filler layer is also provided above the spray section.

5. The electrochemical oxidation device according to claim 1, characterized in that, The electrolyte is a 2M sodium chloride electrolyte.

6. The electrochemical oxidation device according to claim 1, characterized in that, A pump body is installed on the pipeline between the liquid outlet and the liquid inlet.

7. The electrochemical oxidation device according to claim 1, characterized in that, The spray section includes a first pipe connected to the liquid inlet, the first pipe extending horizontally in the gas-liquid mixing chamber, and a plurality of spray nozzles disposed at the lower part of the first pipe facing the first packing layer; the jet section includes a second pipe connected to the air inlet, the second pipe extending horizontally in the gas-liquid mixing chamber, and a plurality of jet nozzles disposed at the upper part of the second pipe facing the first packing layer.

8. The electrochemical oxidation device according to claim 1, characterized in that, The side of the reaction chamber is provided with an installation port and a cover plate rotatably disposed on the installation port. A plurality of first electrodes are spaced apart on the inner side of the cover plate. When the cover plate and the installation port are sealed and overlapped, the first electrodes and the second electrodes are arranged in an alternating manner.

9. The electrochemical oxidation device according to claim 4, characterized in that, Both the first packing layer and the second packing layer are Pall ring packings.

10. A treatment system for treating ammonia nitrogen wastewater, characterized in that, include: The pH adjusting tank includes a first inlet formed on one side for receiving ammonia nitrogen wastewater and a second inlet formed on the other side for receiving alkaline reagents, and an outlet formed on the other side for discharging alkaline ammonia nitrogen wastewater. A stripping tower, the stripping tower including a third inlet formed on one side for receiving the alkaline ammonia nitrogen wastewater and a jet outlet for receiving gas, and an exhaust outlet formed on the upper part for discharging ammonia gas, and a heater for heating the alkaline ammonia nitrogen wastewater is provided inside. The electrochemical oxidation apparatus according to any one of claims 1 to 9, wherein the air inlet is connected to the exhaust port via a pipeline.

Images