Low-temperature wet plasma pulse wave wastewater treatment system and treatment process thereof

Abstract

The invention discloses a low-temperature wet-type plasma pulse wave wastewater treatment system and a low-temperature wet-type plasma pulse wave wastewater treatment process in order to solve the problems that existing high-concentration organic wastewater treatment efficiency is low, and electrodes are prone to scaling. The system comprises a pretreatment unit, a reaction conveying unit, a core reaction unit, a plasma generation and control system, a cooling circulation system and a post-treatment unit. The core reaction unit comprises a reaction tower provided with an arc plasma torch and a high-frequency induction heating assembly. A plasma power supply is integrated with an electronic pulse frequency generator, and electrode scaling is prevented by generating a nanosecond-level automatic reversal polarity signal and utilizing coulomb repulsive force. The process comprises the steps of pretreatment, preheating starting, continuous oxidation and aftertreatment. The high-pressure air generates jet flow containing high-energy electrons and free radicals in the plasma torch, chain reaction is initiated to generate hydroxyl free radicals, pollutants are efficiently oxidized and decomposed, and efficient and stable treatment of high-concentration wastewater is achieved.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment equipment, specifically to a low-temperature wet plasma pulse wave wastewater treatment system and its treatment process. Background Technology

[0002] With the acceleration of industrialization, the treatment of high-concentration, recalcitrant industrial wastewater has become a major challenge in the field of environmental protection. Traditional wastewater treatment technologies have revealed many limitations when dealing with complex industrial wastewater, making it urgent to develop more efficient and economical treatment technologies.

[0003] In recent years, the combination of plasma technology and wet oxidation technology has provided a new solution for the treatment of high-concentration wastewater. Chinese patent CN118221253A discloses a plasma-assisted wet oxidation system for treating high-concentration wastewater. This system achieves efficient COD degradation under catalyst-free conditions through a combination of an inclined plate sedimentation tank, a plunger pump, a heat exchanger, and a plasma wet oxidation reactor. Chinese patent CN109748375A discloses a low-temperature plasma-assisted system for treating recalcitrant organic wastewater. This system employs a low-temperature plasma generator and a supercritical water oxidation reactor working in synergy, effectively improving oxidation efficiency and shortening reaction time. Chinese patent CN113443769A describes an energy-saving wastewater treatment system based on wet oxidation, which achieves effective energy recovery and utilization through the cooperation of a cooling preheating system and a microchannel mixing system.

[0004] However, existing technologies still have significant technical shortcomings. While traditional evaporation methods offer clear treatment effects, they are extremely energy-intensive and prone to concentrating salts and heavy metals, generating hazardous waste. Biological treatment methods have strict requirements for influent water quality, struggle to treat recalcitrant organic matter and high-color wastewater, and produce large amounts of biological sludge. Membrane separation methods face severe membrane fouling problems, have high equipment investment costs, and require secondary treatment of the concentrate. Regarding advanced oxidation technologies, ozone methods, while possessing strong oxidation capabilities, are expensive, energy-intensive, and prone to producing toxic byproducts. Photocatalysis is limited by light source conditions and struggles to treat high-concentration wastewater. Traditional Fenton methods cannot generate effective chain reactions, have short free radical lifetimes, and, more seriously, existing plasma treatment systems commonly suffer from electrode passivation and scaling problems, requiring frequent cleaning or electrode replacement. This severely impacts the system's continuous operational stability and the feasibility of industrial applications. Summary of the Invention

[0005] To address the technical problems of high energy consumption, poor treatment effect, and easy scaling of equipment in traditional wastewater treatment methods when treating high-concentration, recalcitrant industrial wastewater, this invention provides a low-temperature wet plasma pulse wave wastewater treatment system and its treatment process.

[0006] The technical solution adopted by the present invention to solve its technical problem is: to provide a low-temperature wet plasma pulse wave wastewater treatment system, including a pretreatment unit, a reaction and delivery unit, a core reaction unit, a plasma generation and control system, a cooling circulation system and a post-treatment unit.

[0007] Preferably, the pretreatment unit includes an inclined plate sedimentation tank, which is divided into a mixing chamber, a reaction chamber and a sedimentation separation chamber in sequence along the water flow direction by a partition, and is configured to mix the raw wastewater with chemicals and separate the solids and liquids.

[0008] Preferably, the reaction delivery unit includes a plunger pump and a heat exchanger; the heat exchanger is provided with a cold side channel and a hot side channel, the cold side channel is used for preheating the feed, and the hot side channel is used for cooling the discharge.

[0009] Preferably, the core reaction unit includes a plasma wet oxidation reaction tower, an electric arc plasma torch installed on the top of the tower, and a high-frequency induction heating assembly disposed on the outer wall of the tower; the high-frequency induction heating assembly includes an induction coil wound around the outer wall of the tower and a high-frequency heating power supply electrically connected to the induction coil, used to rapidly preheat the tower body and the wastewater inside the tower during the start-up phase through electromagnetic induction.

[0010] Furthermore, the plasma power supply has a special pulse generation function. The plasma power supply integrates an electronic pulse frequency generator, which is configured to generate a nanosecond-level automatic polarity reversal signal. The plasma power supply controls the voltage polarity output to the arc plasma torch to perform nanosecond-level periodic reversal according to the signal, and uses alternating electric field force to prevent scale formation on the electrode surface.

[0011] Optionally, the plasma wet oxidation reaction tower is equipped with a feed nozzle inside. The feed nozzle is a spiral solid nozzle with a spray angle of 60° or 90°. The nozzles are evenly arranged around the circumference of the tower, and the number is a multiple of 2 or 3.

[0012] The present invention also provides a wastewater treatment process using the above system, including a precisely controlled start-up stage: first, the reaction tower is heated to 160°C and 1MPa by a high-frequency induction heating component, and then the cooling system, air compressor and power supply are started in sequence until the temperature reaches 200°C and operates stably.

[0013] Furthermore, during normal operation, the plasma power supply is used to control the electrodes to perform nanosecond-level automatic polarity reversal, and the charge reversal is used to peel off the deposits on the electrode surface; and the hot side channel and cold side channel of the heat exchanger are used to exchange heat and recover heat energy.

[0014] The chain reaction in the process includes: air as the working gas generates an active plasma jet containing high-energy electrons, oxygen positive and negative particles, ozone, and ultraviolet light under the action of a plasma electric field; the active plasma jet is mixed with wastewater, oxygen is ionized to generate oxygen free radicals, oxygen free radicals react with water to generate hydroxyl free radicals, and hydroxyl free radicals further induce chain propagation reactions; the hydroxyl free radicals are used to oxidize organic pollutants into carbon dioxide and water, oxidize ammonia nitrogen into nitrogen gas, and oxidize sulfides into elemental sulfur precipitates or sulfates.

[0015] The beneficial effects of this invention are as follows: Compared with the prior art, this invention has the following technical advantages: high-efficiency degradation and zero discharge, through chain reaction to continuously generate strong oxidizing hydroxyl radicals, rapidly decomposing COD and ammonia nitrogen, and the treated water can be reused, achieving zero liquid discharge; anti-scaling and anti-corrosion, the unique nanosecond-level automatic polarity reversal technology completely solves the problems of electrode passivation and scaling, while the pulse wave can form a magnetic layer on the metal surface, slowing down equipment corrosion; extremely low operating cost, no need to add a large amount of chemical reagents, utilizing its own reaction heat and heat exchanger energy saving, the operating cost is only 0.05-0.50 Singapore dollars / cubic meter; precise process parameters, specific pretreatment speed, settling Reynolds number and start-up temperature curve, ensure the stable industrial operation of the system; significant practical application effect, the case of treating Jinzhou Feng'an coking wastewater shows that the ammonia nitrogen after treatment is almost zero, and the COD removal rate exceeds 74%. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the low-temperature wet plasma pulse wave wastewater treatment system of the present invention; Figure 2 This is a schematic diagram of the inclined plate sedimentation tank in this invention; Figure 3 This is a schematic diagram of the installation structure of the plasma wet oxidation reaction tower and the electric arc plasma torch of the present invention. Figure 4 This is a flowchart of the wastewater treatment process of the present invention. Detailed Implementation

[0017] The present application will be further described in detail below with reference to the accompanying drawings, so that those skilled in the art can better understand and implement the present invention, but the embodiments described are not intended to limit the present invention.

[0018] Example 1

[0019] like Figure 1 As shown, a low-temperature wet plasma pulse wave wastewater treatment system includes a pretreatment unit, a reaction delivery unit, a core reaction unit, a plasma generation and control system, a cooling circulation system, and a post-treatment unit.

[0020] The pretreatment unit includes an inclined plate settling tank 1. For example... Figure 2As shown, the inclined plate sedimentation tank 1 is divided into a mixing chamber, a reaction chamber, and a sedimentation separation chamber by partitions. The mixing chamber is equipped with a dosing device (such as a metering pump and a stirrer) to receive the raw wastewater and add the appropriate flocculant or precipitant. The mixture is then uniformly mixed using a stirrer with a speed set at 40-100 r / min. Stirring continues in the reaction chamber to ensure the chemicals react fully with the wastewater. The sedimentation separation chamber is equipped with inclined tubes (or inclined plates) to increase the sedimentation area using the shallow tank principle. The Reynolds number of the wastewater is strictly controlled to be less than 400, and the hydraulic load is controlled at 9-30 m³ / m²h. The flocs formed by the wastewater and chemicals are separated in the inclined tube area. Suspended solids and heavy metal precipitates fall to the bottom and are discharged, while the supernatant overflows into the water chamber.

[0021] The reaction delivery unit includes a plunger pump 2 and a heat exchanger 3. The inlet of the plunger pump 2 is connected to the outlet of the sedimentation separation chamber of the inclined plate sedimentation tank 1, used to pressurize and transport the clarified liquid after removing suspended solids. The heat exchanger 3 is a shell-and-tube or plate heat exchanger, its main function being to recover the system's heat energy to reduce energy consumption. The heat exchanger 3 has physically isolated but heat-conducting cold-side and hot-side channels. The inlet of the cold-side channel is connected to the outlet of the plunger pump 2, and the outlet of the cold-side channel is connected to the feed inlet of the plasma wet oxidation reaction tower 7. When the low-temperature wastewater to be treated flows through the cold-side channel, it absorbs heat from the hot-side channel to achieve preheating, thereby reducing the energy required for heating the subsequent core reaction unit.

[0022] The core reaction unit includes a plasma wet oxidation reactor 7, an electric arc plasma torch 11 installed on top of the plasma wet oxidation reactor 7, and a high-frequency induction heating assembly. The plasma wet oxidation reactor 7 is the core reaction vessel of this system, made of high-temperature, high-pressure, and corrosion-resistant materials (such as titanium or Hastelloy), and its function is to provide a high-temperature, high-pressure reaction environment for the wastewater and plasma. The feed inlet of the reactor 7 is connected to the cold-side channel outlet of the heat exchanger 3 to receive the preheated wastewater; the gas-liquid two-phase flow outlet of the reactor 7 is connected to the hot-side channel inlet of the heat exchanger 3 to discharge the high-temperature fluid after the reaction.

[0023] The plasma generation and control system includes a high-pressure air compressor system 4 and a plasma power supply 5. The outlet of the high-pressure air compressor system 4 is connected to the working gas inlet of the arc plasma torch 11 to provide clean air (working gas) that has undergone oil and dust removal treatment. The pressure is 0.2 MPa higher than the pressure inside the reaction tower to prevent backflow of gas inside the reaction tower. The plasma power supply 5 integrates an electronic pulse frequency generator, configured to generate a nanosecond-level automatic polarity reversal signal. The plasma power supply 5 controls the voltage polarity output to the arc plasma torch 11 to perform nanosecond-level periodic reversal according to this signal. Using the alternating electric field force, the calcium and magnesium ions or oxide layers that tend to deposit on the electrode surface are detached, thereby preventing scale formation on the electrode surface.

[0024] The cooling circulation system includes a deionized water cooling tower and a deionized water pump. Although the reaction tower operates at high temperatures, the central electrode of the arc plasma torch 11 reaches extremely high temperatures (up to several thousand degrees Celsius), which would lead to electrode ablation if not cooled. Therefore, the deionized water pump pumps deionized water into the internal cooling channel of the arc plasma torch 11 for forced circulation cooling, and then returns it to the deionized water cooling tower for heat dissipation, ensuring that the plasma torch itself is not damaged while generating high-temperature jets.

[0025] The post-treatment unit includes a gas-liquid separator 9 and a deacidification tower 8. The gas-liquid two-phase flow outlet of the reaction tower 7 is cooled via the hot side channel of the heat exchanger 3 and then connected to the inlet of the gas-liquid separator 9. The separated gas enters the deacidification tower 8, where acidic gases are absorbed by alkaline spray before being discharged.

[0026] The wastewater treatment process of this system includes the following steps:

[0027] S1: Pretreatment Steps: High-concentration wastewater enters the mixing chamber of inclined plate sedimentation tank 1. Appropriate reagents are added according to the type of suspended solids and heavy metal ions in the wastewater, and the agitator is started and stirred at 40-100 r / min for 10-30 min. The mixture enters the sedimentation separation chamber, controlling the Reynolds number in the sedimentation separation chamber to be less than 400, the hydraulic load to be 9-30 m³ / m²h, and the wastewater retention time to be 20-40 min. The separated precipitate is discharged into the sludge tank, and the supernatant enters the water chamber.

[0028] S2: System Startup Procedure: The wastewater from which suspended solids have been removed is pumped into the plasma wet oxidation reactor 7 via plunger pump 2 until the designated liquid level is reached. The gas-liquid two-phase flow outlet valve of the plasma wet oxidation reactor 7 and plunger pump 2 are closed. The high-frequency heating power supply is started, and the temperature inside the reactor is heated to 160°C via an induction coil wound around the reactor wall, while maintaining the pressure inside the reactor at 1 MPa during this process. When the temperature reaches 160°C, the fan of the deionized water cooling tower, the deionized water pump, and the high-pressure air compressor 4 system are started sequentially. After a 1-minute delay, the plasma power supply 5 is started to excite the plasma. When the outlet temperature inside the reactor reaches 200°C, this temperature and 1 MPa pressure are maintained for 5 minutes to complete the startup phase. During startup, as the arc plasma torch 11 operates, the power of the high-frequency heating power supply is adaptively reduced to maintain the temperature inside the reactor at a stable 200°C, with a deviation not exceeding 5%.

[0029] S3: Normal Oxidation Operation Procedure: Open the gas-liquid two-phase flow outlet valve and restart the plunger pump 2, allowing the wastewater to continuously flow through the cold side channel of the heat exchanger 3 for preheating before being injected into the plasma wet oxidation reactor 7. Air, pressurized and degreased by the high-pressure air compressor 4 system, enters the electric arc plasma torch 11, where, under the action of the plasma electric field, an active plasma jet containing high-energy electrons, oxygen positive and negative particles, ozone, and ultraviolet light is generated. The active plasma jet mixes with the injected wastewater droplets within the tower, undergoing a chain reaction to generate hydroxyl radicals, oxidizing and decomposing the pollutants in the wastewater. The operating pressure of the plasma wet oxidation reactor 7 is controlled at 0.1-1.0 MPa, the operating temperature at 60-300℃, and the reaction time at 10-30 min. The air pressure provided by the high-pressure air compressor 4 system is set to be 0.2 MPa higher than the internal pressure of the plasma wet oxidation reactor 7. The plasma power supply 5 controls the electrodes to automatically reverse polarity in nanoseconds, using charge reversal to peel off deposits from the electrode surface. The chain reaction includes: oxygen ionization to generate oxygen free radicals, which react with water to generate hydroxyl free radicals, which further induce chain propagation reactions. Hydroxyl free radicals are used to oxidize organic pollutants into carbon dioxide and water, oxidize ammonia nitrogen into nitrogen gas, and oxidize sulfides into elemental sulfur precipitates or sulfates.

[0030] S4: Post-treatment steps: After the reaction, the gas and liquid phases flow through the hot side channel of heat exchanger 3 and exchange heat with the feed cold wastewater flowing through the cold side channel to cool down, and then enter the gas-liquid separator 9. The separated liquid is discharged into the liquid storage tank 10, and the separated gas enters the deacidification tower 8, is neutralized with alkali solution, and then discharged.

[0031] This system achieves highly efficient treatment of high-concentration wastewater through the synergistic effect of multi-stage treatment processes. The pretreatment unit effectively removes suspended solids and heavy metals, creating favorable conditions for subsequent plasma treatment. The plasma technology in the core reaction unit generates highly oxidizing hydroxyl radicals, which can completely decompose organic pollutants. Electrode polarity reversal technology effectively prevents scaling, ensuring long-term stable operation of the equipment. The heat exchanger 3 enables heat energy recovery and utilization, improving system energy efficiency. The post-treatment unit ensures that the final effluent and exhaust gas meet emission standards. In its application to treat wastewater from Jinzhou Feng'an Coking Plant, the entire system achieved near-zero ammonia nitrogen and a COD removal rate exceeding 74%, demonstrating excellent treatment performance.

[0032] Example 2

[0033] This embodiment provides a low-temperature wet plasma pulse wave wastewater treatment system, which mainly consists of a pretreatment unit, a reaction delivery unit, a core reaction unit, a plasma generation and control system, a cooling circulation system, and a post-treatment unit. The pretreatment unit includes an inclined plate settling tank 1; the reaction delivery unit includes a plunger pump 2 and a heat exchanger 3; the core reaction unit includes a plasma wet oxidation reaction tower 7; the plasma generation and control system includes an air compressor 4, a power supply 5, and an electric arc plasma torch 11; the cooling circulation system includes a cooling system 6; and the post-treatment unit includes a deacidification tower 8, a separator 9, and a storage tank 10.

[0034] The pretreatment unit includes an inclined plate settling tank 1, which contains a mixing chamber, a reaction chamber, and a settling separation chamber. The mixing chamber is used to add chemicals to the raw wastewater. Appropriate flocculants or precipitants are added based on the type of suspended solids and heavy metal ions in the wastewater. The agitator speed is set to 40-100 r / min. In the reaction chamber, stirring continues to ensure the chemicals react fully with the wastewater. The agitator speed is maintained at 40-100 r / min, and the reaction time is 10-30 min. The settling separation chamber is equipped with inclined tubes. The Reynolds number of the wastewater in the settling separation chamber is strictly controlled to be less than 400, the hydraulic load is controlled at 9-30 m³ / m²h, and the wastewater retention time is 20-40 min. The flocs formed by the wastewater and chemicals are separated in the inclined tube area. Suspended solids and heavy metal precipitates fall to the bottom and are scraped to the sludge area by a scraper for discharge, thus achieving solid-liquid separation pretreatment of the raw wastewater.

[0035] The reaction delivery unit includes a plunger pump 2 and a heat exchanger 3. The inlet of the plunger pump 2 is connected to the outlet of the inclined plate settling tank 1, and is used to transport the pretreated clarified liquid to the subsequent treatment unit. The heat exchanger 3 is connected between the plunger pump 2 and the feed inlet of the plasma wet oxidation reaction tower 7 to realize heat exchange between the feed and the discharge, thereby improving the thermal efficiency of the system.

[0036] The core reaction unit includes a plasma wet oxidation reaction tower 7, an electric arc plasma torch 11 installed on the tower, a high-frequency heating power supply, and a high-frequency induction heating assembly installed on the outer wall of the tower. The plasma wet oxidation reaction tower 7 is the main reaction vessel, with internal pressure controlled at 0.1-1.0 MPa, temperature controlled at 60-300℃, and wastewater retention time at 10-30 minutes. The electric arc plasma torch 11, installed on the reaction tower, is used to convert the input air into a plasma jet containing high-energy electrons, oxygen positive and negative particles, ozone, ultraviolet light, and other active particles. The high-frequency induction heating assembly includes an induction coil and a high-frequency heating power supply 5, configured to heat the tower body through electromagnetic induction during the startup phase, raising the internal temperature to 160℃ and maintaining a pressure of 1 MPa, creating initial conditions for normal system operation.

[0037] The plasma generation and control system includes a high-pressure air compressor system 4 and a plasma power supply 5. The high-pressure air compressor system 4 is connected to the arc plasma torch 11, providing working gas with a pressure 0.2 MPa higher than the pressure inside the reaction tower. The air, after being degreased and dust-removed, is fed into the arc plasma torch 11. The plasma power supply 5 is electrically connected to the arc plasma torch 11. Under the action of the electric field force generated by the plasma power supply 5, the air is ionized into plasma. The plasma power supply 5 integrates an electronic pulse frequency generator, configured to generate a nanosecond-level automatic polarity reversal signal to control the polarity reversal of the output voltage. Through nanosecond-level polarity reversal, the alternating electric field force is used to peel off dirt from the electrode surface, effectively preventing scaling and ensuring long-term stable operation of the equipment.

[0038] The cooling circulation system includes a deionized water cooling tower and a deionized water pump. The deionized water pump is configured to pump deionized water into the arc plasma torch 11 for cooling and then return it to the deionized water cooling tower, forming a closed-loop cooling system 6. The deionized water cooling tower is equipped with an axial flow fan, which ensures that the arc plasma torch 11 operates at a suitable temperature through forced convection heat dissipation.

[0039] The post-treatment unit includes a gas-liquid separator 9 and a deacidification tower 8. The plasma wet oxidation reactor 7 has a gas-liquid two-phase flow outlet, which is connected to the gas-liquid separator 9 via the hot side channel of the heat exchanger 3. The gas-liquid separator 9 separates the gas and liquid phases after the reaction; the separated liquid enters a liquid storage tank 10 for reuse or discharge after meeting standards. The gas outlet of the gas-liquid separator 9 is connected to the deacidification tower 8, which is equipped with an alkali tank and an alkali circulation pump. The gas is absorbed and neutralized by the alkali in the deacidification tower 8 before being discharged.

[0040] The system works as follows: wastewater is heated by exchanging heat with the high-temperature fluid discharged from the top of the tower via heat exchanger 3, and then sprayed into the tower through a spiral nozzle to form a mist. The plasma jet mixes with the wastewater droplets, continuously generating hydroxyl radicals through a chain reaction. Hydroxyl radicals have strong oxidizing properties, oxidizing COD into carbon dioxide and water, ammonia nitrogen into nitrogen gas, and hydrogen sulfide into elemental sulfur, thereby achieving deep treatment of wastewater.

[0041] Example 3

[0042] This embodiment provides a wastewater treatment process utilizing a low-temperature wet plasma pulse wave wastewater treatment system. The system mainly consists of a pretreatment unit, a reaction delivery unit, a core reaction unit, a plasma generation and control system, a cooling circulation system, and a post-treatment unit.

[0043] The pretreatment unit includes an inclined plate settling tank 1, which contains a mixing chamber, a reaction chamber, and a sedimentation separation chamber for chemical mixing and solid-liquid separation of the raw wastewater. The reaction delivery unit includes a plunger pump 2 and a heat exchanger 3, with the inlet of the plunger pump 2 connected to the outlet of the inclined plate settling tank 1. The core reaction unit includes a plasma wet oxidation reaction tower 7, an electric arc plasma torch 11 installed on the tower, and a high-frequency heating power supply. The heat exchanger 3 is connected between the plunger pump 2 and the feed inlet of the plasma wet oxidation reaction tower 7, and the high-frequency heating power supply is configured to heat the tower body during the start-up phase.

[0044] The plasma wet oxidation reactor 7 is equipped with feed nozzles inside. The feed nozzles are spiral solid nozzles with a spray angle of 60° or 90°. The nozzles are evenly arranged around the circumference of the tower, and the number is a multiple of 2 or 3. This spiral solid nozzle design can create a good atomization effect for the wastewater in the tower, increase the contact area between the wastewater and the plasma, and improve the reaction efficiency.

[0045] The plasma generation and control system includes a high-pressure air compressor system 4 and a plasma power supply 5. The high-pressure air compressor system 4 is connected to the arc plasma torch 11 to provide the working gas, and the plasma power supply 5 is electrically connected to the arc plasma torch 11. The cooling circulation system includes a deionized water cooling tower and a deionized water pump. The deionized water pump is configured to pump deionized water into the arc plasma torch 11 for cooling and return it to the deionized water cooling tower. The post-processing unit includes a gas-liquid separator 9 and a deacidification tower 8. The plasma wet oxidation reaction tower 7 has a gas-liquid two-phase flow outlet, which is connected to the gas-liquid separator 9 via the hot side channel of the heat exchanger 3. The gas outlet of the gas-liquid separator 9 is connected to the deacidification tower 8.

[0046] The specific wastewater treatment process includes the following steps:

[0047] Step 1: Preprocessing

[0048] High-concentration wastewater enters the mixing chamber of inclined plate sedimentation tank 1. Appropriate flocculants or precipitants are added based on the type of suspended solids and heavy metal ions in the wastewater. The agitator is started and stirred at 40-100 r / min for 10-30 min to ensure thorough mixing and reaction between the agents and wastewater. The mixture then enters the sedimentation separation chamber, where the Reynolds number is controlled to be less than 400, the hydraulic load to be 9-30 m³ / m²h, and the wastewater retention time to be 20-40 min. Under these strictly controlled process parameters, the flocs formed by the wastewater and the agents are effectively separated in the inclined plate zone. The separated precipitate is discharged into the sludge tank, and the supernatant enters the water chamber.

[0049] Step Two: System Startup Phase

[0050] Wastewater from which suspended solids have been removed is pumped into the plasma wet oxidation reactor 7 via plunger pump 2 until the designated liquid level is reached. The gas-liquid two-phase flow outlet valve of the plasma wet oxidation reactor 7 and plunger pump 2 are then closed. The high-frequency heating power supply 5 is started to heat the temperature inside the reactor to 160°C, maintaining the pressure inside the reactor at 1 MPa during this process. When the temperature reaches 160°C, the fan, deionized water pump, and high-pressure air compressor 4 of the deionized water cooling system 6 are started sequentially. After a 1-minute delay, the plasma power supply 5 is started to generate plasma. When the outlet temperature inside the reactor reaches 200°C, this temperature and 1 MPa pressure are maintained for 5 minutes to complete the start-up phase. This start-up process ensures that the plasma wet oxidation reactor 7 reaches a stable operating state, laying the foundation for subsequent continuous processing.

[0051] Step 3: Continuous Reaction Processing

[0052] Open the gas-liquid two-phase flow outlet valve and restart the plunger pump 2, allowing the wastewater to continuously flow through the cold side channel of the heat exchanger 3 for preheating before being sprayed into the plasma wet oxidation reaction tower 7. After the wastewater exchanges heat with the high-temperature fluid flowing through the hot side channel at the top of the tower via the heat exchanger 3, it is heated and then sprayed into the tower through a spiral solid nozzle, forming a mist. Air is pressurized and degreased by the high-pressure air compressor 4 system before entering the arc plasma torch 11, where it generates an active plasma jet containing high-energy electrons, oxygen positive and negative particles, ozone, and ultraviolet light under the action of the plasma electric field.

[0053] The active plasma jet mixes with the injected wastewater droplets within the plasma wet oxidation reactor 7, triggering a chain reaction to generate hydroxyl radicals. Specifically, oxygen molecules decompose into oxygen atoms under the influence of plasma (O2→O′+O′), and these oxygen atoms react with water molecules to generate hydroxyl radicals (O′+H2O→HO′+HO′). These hydroxyl radicals possess strong oxidizing properties, oxidizing and decomposing pollutants in the wastewater. COD is oxidized to carbon dioxide and water, ammonia nitrogen is oxidized to nitrogen gas, and hydrogen sulfide is oxidized to elemental sulfur. The plasma wet oxidation reactor 7 operates under the following conditions: pressure 0.1-1.0 MPa, temperature 60-300℃, and residence time 10-30 min.

[0054] Step 4: Post-processing steps

[0055] After the reaction, the gas and liquid phases flow through the hot side channel of heat exchanger 3, where they exchange heat with the feed cold wastewater to cool down before entering the gas-liquid separator 9. The separated liquid is discharged into liquid storage tank 10, where it can be reused or discharged in compliance with standards; the separated gas enters deacidification tower 8, where it is neutralized with alkali before being discharged. This heat exchange process not only reduces the discharge temperature but also preheats the feed wastewater, achieving effective energy recovery and utilization.

[0056] In a preferred embodiment, the nozzle spray angle can be selected as 60°. This angle design can ensure the atomization effect while allowing the wastewater to have a longer residence time in the plasma wet oxidation reaction tower 7, thereby improving the treatment effect.

[0057] In another preferred embodiment, the nozzle spray angle can also be selected as 90°. This vertical spraying method can make the wastewater droplets more evenly distributed in the plasma wet oxidation reaction tower 7 and fully contact the plasma jet.

[0058] This process utilizes high-energy active particles generated by the plasma technology of the electric arc plasma torch 11 to efficiently oxidize and decompose organic pollutants and ammonia nitrogen in wastewater, achieving significant treatment results. The ammonia nitrogen removal rate is close to 100%, and the COD removal rate exceeds 74%, providing an effective technical solution for the treatment of high-concentration, recalcitrant wastewater.

[0059] According to the error message, corresponding numbers need to be added to each component in the patent text. However, the provided patent text is only a conclusion paragraph and does not include the specific components mentioned in the error message (sloping plate settling tank, plunger pump, heat exchanger, etc.).

[0060] Since the error message indicates a problem with missing numbering after component names in the specific implementation, and these component names do not appear in the currently provided text paragraph, this text itself does not need to be modified.

[0061] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A low-temperature wet plasma pulse wave wastewater treatment system, characterized in that, include: The pretreatment unit includes an inclined plate sedimentation tank, which is internally divided into a mixing chamber, a reaction chamber, and a sedimentation separation chamber along the water flow direction by partitions. The mixing chamber is equipped with a dosing device and is configured to rapidly mix the raw wastewater with chemicals. The reaction chamber is located between and connected to the mixing chamber and the sedimentation separation chamber, and is configured to provide a slow stirring environment for the mixed wastewater to undergo a flocculation reaction, thereby forming easily settling flocs. The inclined plate sedimentation tank is configured to perform chemical mixing and solid-liquid separation of the raw wastewater, and the supernatant after separation enters the sedimentation separation chamber. The reaction delivery unit includes a plunger pump and a heat exchanger. The inlet of the plunger pump is connected to the outlet of the sedimentation separation chamber of the inclined plate sedimentation tank. The heat exchanger, as a heat energy recovery component of the system, is provided with a physically isolated cold side channel and a heat side channel that can conduct heat. The inlet of the cold-side channel is connected to the outlet of the plunger pump and is configured to receive low-temperature wastewater and preheat it using heat exchange; the hot-side channel is configured to receive the high-temperature fluid after the reaction and release heat to the cold-side channel. The core reaction unit includes a plasma wet oxidation reaction tower, an electric arc plasma torch installed on the top of the plasma wet oxidation reaction tower, and a high-frequency induction heating assembly disposed on the outer wall of the plasma wet oxidation reaction tower; the outlet of the cold side channel of the heat exchanger is connected to the feed inlet of the plasma wet oxidation reaction tower; the plasma wet oxidation reaction tower, as a high-temperature and high-pressure reaction vessel, is configured to provide a site for mixing and reacting wastewater with plasma jets; the high-frequency induction heating assembly includes an induction coil wound around the outer wall of the plasma wet oxidation reaction tower and a high-frequency heating power supply electrically connected to the induction coil, configured to heat the tower body and the wastewater inside the tower through electromagnetic induction during the start-up phase; A plasma generation and control system includes a high-pressure air compressor system and a plasma power supply. The high-pressure air compressor system is connected to the working gas inlet of the arc plasma torch to provide pressurized working gas, and the plasma power supply is electrically connected to the arc plasma torch to provide excitation voltage. A cooling circulation system includes a deionized water cooling tower and a deionized water pump, wherein the deionized water pump is configured to pump deionized water into the cooling jacket of the arc plasma torch for cooling and then return it to the deionized water cooling tower. The post-treatment unit includes a gas-liquid separator and a deacidification tower; the plasma wet oxidation reaction tower is provided with a gas-liquid two-phase flow outlet, which is connected to the inlet of the gas-liquid separator via the hot side channel of the heat exchanger. The hot side channel is configured to cool the high-temperature gas-liquid mixture flowing out of the plasma wet oxidation reaction tower and transfer the heat to the low-temperature wastewater in the cold side channel; the gas outlet of the gas-liquid separator is connected to the deacidification tower.

2. The low-temperature wet plasma pulse wave wastewater treatment system according to claim 1, characterized in that: The plasma power supply integrates an electronic pulse frequency generator, configured to generate a nanosecond-level automatic polarity reversal signal. The plasma power supply controls the voltage polarity output to the arc plasma torch to perform a nanosecond-level periodic reversal based on this signal, using alternating electric field force to prevent scale buildup on the electrode surface.

3. The low-temperature wet plasma pulse wave wastewater treatment system according to claim 1, characterized in that: The plasma wet oxidation reaction tower is equipped with a feed nozzle, which is a spiral solid nozzle with a spray angle of 60° or 90°. The nozzles are evenly arranged around the circumference of the tower and the number is a multiple of 2 or 3.

4. A wastewater treatment process utilizing the low-temperature wet plasma pulse wave wastewater treatment system according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1. Pretreatment Steps: High-concentration wastewater enters the mixing chamber of the inclined plate sedimentation tank. Chemicals are added via a dosing device, and the agitator is started and stirred at 40-100 r / min for 10-30 min. The mixed liquid overflows into the reaction chamber for further reaction and then enters the sedimentation separation chamber. The Reynolds number in the sedimentation separation chamber is controlled to be less than 400, the hydraulic load is 9-30 m³ / m²h, and the wastewater retention time is 20-40 min. The separated precipitate is discharged into the sludge tank, and the supernatant enters the water chamber. S2. System startup steps: The wastewater from which suspended solids have been removed is pumped into the plasma wet oxidation reaction tower via the plunger pump until it reaches the designated liquid level. Close the gas-liquid two-phase flow outlet valve and plunger pump of the plasma wet oxidation reaction tower; The high-frequency heating power supply is started, and the temperature inside the tower is heated to 160°C through the high-frequency induction heating component, while maintaining the pressure inside the tower at 1 MPa during the process; When the temperature reaches 160℃, the fan, deionized water pump and high-pressure air compressor system of the deionized water cooling tower are started in sequence. The plasma power supply is activated after a 1-minute delay to stimulate the plasma. When the outlet temperature inside the tower reaches 200℃, maintain this temperature and 1 MPa pressure for 5 minutes to complete the start-up phase. S3. Normal oxidation operation procedure: Open the gas-liquid two-phase flow outlet valve and restart the plunger pump so that the wastewater flows continuously through the heat exchanger for preheating before being sprayed into the plasma wet oxidation reaction tower; Air, as the working gas, is pressurized and degreased by the high-pressure air compressor system and then enters the electric arc plasma torch. Under the action of the plasma electric field, an active plasma jet containing high-energy electrons, oxygen positive and negative particles, ozone and ultraviolet rays is generated. The active plasma jet mixes with the injected wastewater droplets inside the tower, and a chain reaction occurs to generate hydroxyl radicals, which oxidize and decompose the pollutants in the wastewater. During this process, the plasma power supply controls the electrodes to automatically reverse polarity to prevent scaling. S4. Post-processing steps: After the reaction, the gas and liquid phases flow through the hot side channel of the heat exchanger and exchange heat with the feed cold wastewater flowing through the cold side channel to cool down before entering the gas-liquid separator. The separated liquid is discharged into a liquid storage tank, and the separated gas enters the deacidification tower, is neutralized with alkali, and then discharged.

5. The wastewater treatment process of the low-temperature wet plasma pulse wave wastewater treatment system according to claim 4, characterized in that: During the start-up process of step S2, as the arc plasma torch operates, the power of the high-frequency heating power supply is adaptively reduced to maintain the temperature inside the tower at 200°C, with a deviation of no more than 5%.

6. The wastewater treatment process of the low-temperature wet plasma pulse wave wastewater treatment system according to claim 4, characterized in that: In step S3, the operating pressure of the plasma wet oxidation reaction tower is controlled at 0.1-1.0 MPa, the operating temperature is controlled at 60-300℃, and the reaction time is 10-30 min; the air pressure provided by the high-pressure air compressor system is set to be 0.2 MPa higher than the internal pressure of the plasma wet oxidation reaction tower.

7. The wastewater treatment process of the low-temperature wet plasma pulse wave wastewater treatment system according to claim 4, characterized in that: In step S3, the plasma power supply control electrode performs automatic polarity reversal, with a reversal time on the order of nanoseconds, and uses charge reversal to peel off the deposits on the electrode surface.

8. The wastewater treatment process of the low-temperature wet plasma pulse wave wastewater treatment system according to claim 4, characterized in that: The chain reaction in step S3 includes: oxygen being ionized to generate oxygen free radicals, oxygen free radicals reacting with water to generate hydroxyl free radicals, and hydroxyl free radicals further inducing chain propagation reactions; using the hydroxyl free radicals to oxidize organic pollutants into carbon dioxide and water, oxidize ammonia nitrogen into nitrogen gas, and oxidize sulfides into elemental sulfur precipitates or sulfates.

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