Normal-temperature delayed oxidation treatment method and device for furniture spray coating exhaust gas

Abstract

This invention relates to the field of waste gas treatment technology, and discloses a method and apparatus for room-temperature delayed oxidation treatment of furniture spraying waste gas. The method includes: introducing waste gas into a reaction chamber filled with an iron-manganese composite modified activated carbon adsorption bed for adsorption and enrichment; after adsorption saturation, opening a closed-loop circulation gas path; blowing in a mixture of vaporized hydrogen peroxide and ozone; using humidity regulation to drive capillary co-condensation of the oxidation medium within micropores; and utilizing iron-manganese bimetallic catalysis for in-situ delayed oxidation regeneration. During operation, the wind speed is alternately switched for pulse flushing, and timed exhaust and replenishment are performed. After the reaction, dry air is introduced for reset. The supporting equipment includes a pretreatment and air intake module, a core reaction module, a power closed-loop circulation module, and an oxidation medium vaporization injection module. This invention achieves room-temperature in-situ chemical regeneration of the adsorbent, reducing energy consumption and improving the continuous and stable operation cycle.

Description

Technical Field

[0001] This invention relates to the field of waste gas treatment technology, specifically to a method and apparatus for room temperature delayed oxidation treatment of furniture spraying waste gas. Background Technology

[0002] Furniture manufacturing processes generate a large amount of spraying waste gas, which contains a large amount of volatile organic pollutants. In order to meet environmental emission standards, enterprises often use adsorption technology to intercept and enrich organic pollutants entering the exhaust pipe. Activated carbon, as the mainstream adsorption material, has a rich microporous structure on its surface, which can trap low concentrations of volatile organic compounds inside the pores, thereby achieving gas-solid separation and meeting emission standards. When the activated carbon bed reaches adsorption saturation, the carbon-based material needs to be regenerated to restore the material's adsorption capacity and ensure continuous waste gas treatment operations.

[0003] Conventional regeneration processes are divided into two categories: physical desorption and chemical oxidation. Physical desorption mainly uses hot air or steam to heat the saturated adsorption bed, so that the organic pollutant molecules adsorbed inside the micropores can gain thermal energy and detach from the adsorption sites. They are then sent into a high-concentration desorption gas stream and sent to an incinerator for high-temperature thermal oxidation. Chemical oxidation, on the other hand, involves introducing ozone or spraying an oxidant solution into the system at room temperature or medium to low temperature. The oxidant molecules come into contact with the organic pollutant molecules, causing the chemical bonds to break, and ultimately converting hydrocarbons into carbon dioxide and water, thereby freeing up the internal space of the activated carbon.

[0004] In conventional room-temperature gas-phase oxidation processes, the mass transfer resistance of oxidant gas molecules on the surface of activated carbon solid micropores is very high, and the contact between the gas and solid phases is insufficient. This makes it difficult to completely degrade large molecular volatile organic pollutants. The carbon dioxide and water generated in the reaction will remain inside the micropores for a long time, causing the partial pressure of the products inside the system to rise continuously, inhibiting the subsequent oxidation reaction. Excessive accumulation of liquid water will also occupy physical adsorption sites, causing the carbon-based materials to lose their ability to intercept pollutants. Due to the combined problems of limited mass transfer and product accumulation, existing room-temperature oxidation technologies cannot achieve deep regeneration of adsorbents.

[0005] Therefore, the purpose of this invention is to provide a method and apparatus for room temperature delayed oxidation treatment of furniture spraying exhaust gas, so as to overcome the shortcomings of the prior art. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method and apparatus for room-temperature delayed oxidation treatment of furniture spraying exhaust gas. This method solves the technical problems in existing room-temperature oxidation technologies, such as high gas-solid mass transfer resistance leading to incomplete degradation of exhaust gas, and reaction products remaining inside micropores inhibiting the forward reaction and occupying physical adsorption sites, ultimately preventing the adsorbent from being deeply regenerated.

[0007] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a method for room temperature delayed oxidation treatment of furniture spraying exhaust gas, employing the following technical solution: A method for room temperature delayed oxidation treatment of furniture spraying exhaust gas includes the following steps: The exhaust gas from furniture spraying is passed into a reaction chamber filled with an iron and manganese composite modified activated carbon adsorption bed, where physical adsorption and enrichment occur until adsorption saturation is reached and then the gas flow is stopped. The reaction chamber is isolated from the outside world and a closed-loop gas circuit is opened. Hydrogen peroxide aqueous solution is vaporized into mixed steam and then mixed with ozone and blown into the reaction chamber. The injection amount of the mixed steam is adjusted in conjunction with the real-time humidity monitoring, driving the oxidation medium composed of the mixed steam and the ozone to undergo capillary co-condensation inside the micropores of the iron and manganese composite modified activated carbon, and carrying out an in-situ delayed oxidation and regeneration reaction. Pulse flushing is performed in the closed-loop recirculating air circuit, alternating between low-frequency reference wind speed and high-frequency jump wind speed; During the alternating operation of the variable frequency, the enriched carbon dioxide gas is discharged to the outside while an equal volume of fresh air is replenished. After the in-situ delayed oxidation and regeneration reaction is completed, the injection of the hydrogen peroxide aqueous solution and the ozone is stopped, the closed-loop circulation gas circuit is closed, and dry air is introduced into the reaction chamber to purge the iron and manganese composite modified activated carbon adsorption bed for system drying and resetting.

[0008] By adopting the above technical solution, using iron and manganese composite modified activated carbon as the adsorption and catalytic carrier, and introducing hydrogen peroxide mixed steam and ozone for synergistic oxidation, combined with a closed-loop circulation and capillary co-condensation mechanism, the treatment effect of in-situ deep regeneration of the adsorbent at room temperature is achieved. The reaction mechanism specifically includes the following steps: The first step is physical adsorption and retention. At room temperature, the large molecular volatile organic compounds in the spraying exhaust gas are retained and enriched in the microporous structure of the iron and manganese composite modified activated carbon, thus achieving gas-solid phase separation.

[0009] The second step involves capillary co-condensation and the construction of a liquid-phase microenvironment. Hydrogen peroxide mixed vapor is injected into the reaction chamber, and the system humidity is adjusted. Utilizing the capillary condensation effect within the micropores, gaseous water molecules and hydrogen peroxide molecules condense into a liquid phase within the activated carbon micropores, thus constructing a liquid-phase microreaction environment. Ozone, carried by the airflow, penetrates the bed and dissolves in this liquid-phase microenvironment, forming a synergistic liquid-phase reaction system of hydrogen peroxide and ozone.

[0010] The third step involves catalytic decomposition and in-situ delayed oxidation. The bimetallic elements iron and manganese synergistically catalyze hydrogen peroxide and ozone at room temperature, promoting a rapid chain decomposition reaction that generates highly oxidizing hydroxyl radicals. Volatile organic compounds enriched in the micropores directly react with these hydroxyl radicals, breaking carbon-hydrogen bonds and undergoing oxidative degradation. The reaction products are converted into carbon dioxide and water. This degradation process is carried out in a sealed, room-temperature environment with a delayed duration, achieving the restoration of the activated carbon's adsorption capacity and chemical regeneration.

[0011] The fourth step is pulse scouring and mass transfer enhancement. Alternating between low-frequency reference wind speed and high-frequency jump wind speed changes the airflow distribution inside the bed, reduces the gas-liquid mass transfer resistance on the microporous surface, accelerates the dissolution and diffusion rate of liquid ozone, and simultaneously promotes the desorption of carbon dioxide generated in the reaction into the main airflow for discharge.

[0012] Preferably, the preparation steps of the iron and manganese composite modified activated carbon specifically include: Washed and dried coal-based columnar activated carbon is immersed in a metal precursor impregnation solution containing ferric nitrate nonahydrate and a 50% (w / w) aqueous solution of manganese nitrate. The mixture is stirred and allowed to stand for impregnation to obtain wet metal-supported activated carbon. After being dried at a constant temperature, the activated carbon is placed in a protective atmosphere and heated to 450°C–550°C at a heating rate of 5°C per minute for constant temperature calcination. The activated carbon is then naturally cooled to room temperature to obtain the iron-manganese composite modified activated carbon. The molar ratio of iron to manganese in the metal precursor impregnation solution is 1:1 to 3:1, and the total mass of iron and manganese accounts for 3%–8% of the mass of the dried coal-based columnar activated carbon.

[0013] By employing the above technical solution, ferric nitrate and manganese nitrate are used as precursor materials for impregnation and isothermal calcination, resulting in the uniform distribution of iron-manganese bimetallic oxides on the surface and within the pores of coal-based columnar activated carbon. An electron transfer effect occurs between the iron-manganese bimetallic lattices, effectively reducing the activation energy for the decomposition of hydrogen peroxide and ozone to generate hydroxyl radicals at room temperature, thus enhancing the catalytic oxidation activity of the material.

[0014] Preferably, the hydrogen peroxide aqueous solution is 30% by mass; the vaporization working temperature is set to 45℃~55℃; and the injection amount of the mixed steam is adjusted to keep the relative humidity inside the reaction chamber stable between 80% and 85%.

[0015] By employing the above technical solution, a vaporization temperature of 45℃ to 55℃ ensures that the hydrogen peroxide solution is converted into gaseous molecules while avoiding extensive thermal decomposition. Maintaining a stable relative humidity within the range of 80% to 85% effectively induces capillary condensation within the micropores, while preventing excessive moisture from causing complete flooding of the micropores and hindering ozone gas diffusion.

[0016] Preferably, the low-frequency reference wind speed is 0.4 m / s, the high-frequency jump wind speed is 1.2 m / s to 1.8 m / s, and the frequency of wind speed alternation is once every 5 minutes.

[0017] By adopting the above technical solution, a wind speed of 0.4 m / s maintains the basic requirements for transporting reactants, while a high-frequency sudden wind speed of 1.2 m / s to 1.8 m / s creates fluid disturbance. The frequency of switching every 5 minutes matches the cycle of gas-liquid two-phase mass transfer and product accumulation, preventing reactant concentration polarization.

[0018] Preferably, during the frequency conversion alternating operation, a small amount of the enriched carbon dioxide gas is momentarily discharged every 10 minutes while an equal volume of fresh air is replenished; the in-situ delayed oxidation regeneration reaction continues for 120 minutes, and dry air is introduced for 60 minutes during system drying and reset.

[0019] By adopting the above technical solution, periodic exhaust and replenishment of gas maintain the dynamic pressure balance of the closed-loop gas circuit, preventing excessive carbon dioxide partial pressure from inhibiting the forward reaction. A 120-minute delayed oxidation time provides the reaction time required for degradation, and a 60-minute drying and purging process removes residual free moisture inside the micropores, restoring the physical adsorption capacity of the activated carbon.

[0020] Secondly, the present invention provides a room temperature delayed oxidation treatment device for furniture spraying exhaust gas, which adopts the following technical solution: A room temperature delayed oxidation treatment device for furniture spraying exhaust gas, used to implement the above method, includes a pretreatment and air intake module, a core reaction and detection module, a power closed-loop circulation and exhaust control module, and an oxidation medium vaporization injection module. The output of the pretreatment and air intake module is connected to the air intake of the core reaction and detection module, which is used to intercept and humidify the furniture spraying exhaust gas and send it to the core reaction and detection module. The core reaction and detection module is used to provide a closed space for the adsorption, enrichment and delayed oxidation micro-reaction of waste gas and to monitor the internal temperature and humidity in real time. The closed-loop circulation and exhaust control module is connected to the exhaust side of the core reaction and detection module. It is used to provide fluid transport power to the system and to control the flow and pressure balance between the closed-loop circulation pipeline and the external exhaust. The output end of the oxidation medium vaporization injection module is connected to the end of the closed-loop circulation pipeline of the power closed-loop circulation and exhaust control module, and is used to mix the vaporized hydrogen peroxide mixed vapor with ozone and send it into the core reaction and detection module.

[0021] By adopting the above technical solutions, the various modules work together to form a complete waste gas treatment system. The pretreatment and intake module ensures that the waste gas entering the system meets the treatment conditions; the core reaction and detection module provides the physical space for ambient temperature catalytic oxidation and provides feedback on control parameters; the power closed-loop circulation and exhaust control module establishes an exhaust gas path during the adsorption period and an isolated circulation gas path during the regeneration period; and the oxidation medium vaporization injection module provides gaseous oxidation medium to the circulation gas path, all working together to achieve automated alternating operation.

[0022] Preferably, the pretreatment and air intake module includes an exhaust gas inlet pipe, a fresh air mixing valve is provided at the front end of the exhaust gas inlet pipe, a dry filter is provided on the downstream pipe of the fresh air mixing valve, the dry filter is filled with multi-stage glass fiber filter cotton, an air intake main valve is connected in series at the outlet end of the dry filter, and the output end of the air intake main valve is directly connected to the air intake of the core reaction and detection module.

[0023] By adopting the above technical solutions, the fresh air mixing valve adjusts the humidity of the original exhaust gas by mixing dry air, the dry filter intercepts paint mist and dust particles in the exhaust gas to prevent mechanical blockage of the micropores of the downstream modified activated carbon, and the main air inlet valve cuts off or opens the exhaust gas flow.

[0024] Preferably, the core reaction and detection module includes a sealed reaction chamber. Inside the sealed reaction chamber, a horizontal frame is provided with an iron and manganese composite modified activated carbon adsorption bed with a thickness of 0.4m to 0.8m. A temperature and humidity sensor group is inserted inside the sealed reaction chamber. The probes of the temperature and humidity sensor group are respectively arranged at the bottom of the air inlet side and the top of the air outlet side of the iron and manganese composite modified activated carbon adsorption bed. An exhaust main valve is installed at the top air outlet of the sealed reaction chamber.

[0025] This invention provides a method and apparatus for room-temperature delayed oxidation treatment of furniture painting exhaust gas. It has the following beneficial effects: 1. This invention sets up an iron and manganese composite modified activated carbon adsorption bed and combines it with real-time humidity control to inject hydrogen peroxide mixed steam and ozone, driving the oxidation medium to undergo capillary co-condensation inside the micropores of activated carbon, constructing a liquid-phase micro-reaction environment, and utilizing the catalytic effect of iron and manganese bimetals at room temperature to generate hydroxyl radicals, directly degrading the enriched volatile organic compounds, realizing the room temperature in-situ chemical regeneration of the adsorbent, and reducing the energy consumption of conventional high-temperature desorption processes.

[0026] 2. This invention sets up a closed-loop circulating air path and alternates between low-frequency reference wind speed and high-frequency jump wind speed during operation to generate a pulse scouring effect on the adsorption bed. The dynamic airflow effectively reduces the gas-liquid mass transfer resistance on the surface of activated carbon micropores, accelerates the dissolution and diffusion of ozone, and promotes the desorption and discharge of reaction product carbon dioxide, thereby improving the oxidation and degradation rate of pollutants in the exhaust gas.

[0027] 3. By setting a step of periodically discharging carbon dioxide and replenishing it with an equal volume of fresh air, this invention maintains the dynamic pressure balance inside the closed-loop gas circuit, preventing excessively high product partial pressure from inhibiting the forward reaction. Combined with the reset step of blowing dry air after the reaction, residual moisture inside the micropores is removed, the physical adsorption capacity of the activated carbon is restored, and the stability of the equipment's long-term continuous operation is ensured. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a graph showing the test results of the macroscopic mass distribution and micropore retention characteristics of the oxidation medium of the present invention; Figure 3 This is a graph showing the test results of bed pressure drop and dynamic carbon dioxide emissions during the mid-term regeneration reaction of this invention; Figure 4 This is a graph showing the results of multi-point dynamic temperature rise test of the bed during the oxidation regeneration reaction of the present invention; Figure 5 This is a graph showing the test results of the comprehensive degradation rate and deep mineralization rate of the waste gas in this invention; Figure 6 The figure shows the results of the passivation resistance and lifespan test of the adsorption bed under long-term cyclic operation according to the present invention.

[0029] Among them, 101, fresh air mixing valve; 102, dry filter; 103, main air inlet valve; 200, sealed reaction chamber; 201, iron and manganese composite modified activated carbon adsorption bed; 202, temperature and humidity sensor group; 203, main exhaust valve; 300, variable frequency centrifugal main fan; 301, variable frequency controller; 302, compliant emission port; 401, closed-loop circulation valve; 402, pressure relief and exhaust valve; 403, isobaric air supply valve; 501, hydrogen peroxide storage tank; 502, metering pump; 503, electric heating vaporizer; 504, ozone generator. Detailed Implementation

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] This invention provides a room temperature delayed oxidation treatment device for furniture spraying exhaust gas. The overall structure consists of two parallel pipelines interwoven: an open-circuit treatment gas path and a closed-circuit circulation gas path. The room temperature delayed oxidation treatment device for furniture spraying exhaust gas includes a pretreatment and air intake module, a core reaction and detection module, a power closed-circuit circulation and exhaust control module, and an oxidation medium vaporization injection module.

[0032] Please see the appendix Figure 1 The pretreatment and air intake module is located at the front end of the waste gas delayed oxidation treatment device. The pretreatment and air intake module is used to intercept particulate matter and pre-humidify the original furniture spraying waste gas in the physical adsorption stage. A fresh air mixing valve 101 is installed at the front end of the original waste gas inlet pipe. The fresh air mixing valve 101 is used to draw in dry air from the workshop for pre-humidification when the relative humidity of the original furniture spraying waste gas is higher than the 40% threshold.

[0033] A dry filter 102 is installed on the downstream pipeline of the fresh air mixing valve 101. The dry filter 102 is filled with multi-stage glass fiber filter cotton combining primary and medium efficiency filters. The dry filter 102 can completely intercept paint mist and dust particles with a particle size greater than 1 micrometer, preventing mechanical blockage of the downstream catalyst channels. The outlet end of the dry filter 102 is connected in series with a pneumatic or electrically isolated main air valve 103. The output end of the main air valve 103 is directly connected to the air inlet of the core reaction and detection module.

[0034] The core reaction and detection module is a sealed reaction chamber 200, which is welded from carbon steel or stainless steel. The sealed reaction chamber 200 has the mechanical strength to withstand micro-pressure fluctuations of ±3000Pa. One or more layers of iron and manganese composite modified activated carbon adsorption bed 201 are set in the horizontal frame in the middle cavity of the sealed reaction chamber 200. The thickness of the iron and manganese composite modified activated carbon adsorption bed 201 is controlled in the range of 0.4m to 0.8m. The iron and manganese composite modified activated carbon adsorption bed 201 is filled with customized iron and manganese composite modified activated carbon. The airflow is kept uniformly distributed when passing through the cross-section of the iron and manganese composite modified activated carbon adsorption bed 201.

[0035] A temperature and humidity sensor group 202 is inserted inside the sealed reaction chamber 200. The probes of the temperature and humidity sensor group 202 are respectively arranged at the bottom of the air inlet side and the top of the air outlet side of the iron and manganese composite modified activated carbon adsorption bed 201. The temperature and humidity sensor group 202 is responsible for monitoring the temperature and relative humidity of the reaction microenvironment in real time. At the top air outlet position of the sealed reaction chamber 200, an exhaust main valve 203 responsible for isolating the pipeline network is installed.

[0036] The power, closed-loop circulation, and exhaust control module provides fluid transport power, dynamic shear airflow, and mass balance regulation functions for the entire system. A variable frequency centrifugal main fan 300 is connected to the downstream main pipeline of the exhaust main valve 203. The positive pressure exhaust side end of the variable frequency centrifugal main fan 300 is connected to the compliant emission port 302. The motor signal of the variable frequency centrifugal main fan 300 is connected to the variable frequency controller 301 inside the electrical control cabinet. The PLC program built into the variable frequency controller 301 can drive the variable frequency centrifugal main fan 300 to periodically and rapidly switch between low-frequency reference wind speed and high-frequency sudden wind speed. The waste gas delayed oxidation treatment device is equipped with a closed-loop circulation pipeline.

[0037] One end of the closed-loop circulation pipeline is connected to the tee between the outlet of the variable frequency centrifugal main fan 300 and the standard discharge port 302. The other end of the closed-loop circulation pipeline is connected back to the pipe section between the main air inlet valve 103 and the air inlet of the sealed reaction box 200. A closed-loop circulation valve 401 is installed on the closed-loop circulation pipeline, which is responsible for controlling the on / off state of the airflow.

[0038] Two fine-tuning valves are also installed in parallel on the closed-loop circulation pipeline: the first fine-tuning valve is a pressure relief and exhaust valve 402 facing the external environment. The pressure relief and exhaust valve 402 can discharge a small amount of enriched carbon dioxide gas at a pulse frequency during the regeneration period; the second fine-tuning valve is an isobaric air supply valve 403. The isobaric air supply valve 403 and the pressure relief and exhaust valve 402 operate synchronously. The isobaric air supply valve 403 can replenish fresh air in an equal volume to maintain the air pressure balance inside the closed pipeline network.

[0039] The oxidation medium vaporization injection module provides an oxidation medium that allows for smooth gas-phase penetration and capillary condensation within the micropores. Next to the waste gas delayed oxidation treatment device is a hydrogen peroxide storage tank 501 containing 30% hydrogen peroxide by mass. The hydrogen peroxide storage tank 501 is connected to a metering pump 502, which precisely extracts liquid hydrogen peroxide and delivers it into an electrically heated vaporizer 503. The electrically heated vaporizer 503 has a closed-loop temperature control function, and its operating temperature is set between 45°C and 55°C. The electrically heated vaporizer 503 can completely convert liquid hydrogen peroxide into a mixed vapor of water molecules and hydrogen peroxide molecules.

[0040] The waste gas delayed oxidation treatment device is also equipped with an ozone generator 504 using high-voltage surface discharge technology. The gas phase outlet of the electrically heated vaporizer 503 merges with the gas outlet pipeline of the ozone generator 504. The merging pipeline is connected to the end of the closed-loop circulation pipeline, and the connection point of the merging pipeline is close to the air inlet of the sealed reaction chamber 200.

[0041] Based on the above-mentioned room temperature delayed oxidation treatment device for furniture spraying exhaust gas, the present invention also provides a room temperature delayed oxidation treatment method for furniture spraying exhaust gas, which is described below.

[0042] Preparation Examples 1-3: Preparation Example 1: This preparation example provides a method for preparing iron and manganese composite modified activated carbon, including the following steps: 100 parts of coal-based columnar activated carbon were washed three times in ultrapure water to remove dust and impurities from the surface. They were then dried in a constant-temperature drying oven at 105℃ for 12 hours to obtain pretreated activated carbon. 26.6 parts of ferric nitrate nonahydrate and 11.8 parts of a 50% manganese nitrate aqueous solution were weighed and mixed, then 100 parts of ultrapure water were added and stirred to dissolve, preparing a metal precursor impregnation solution. At this point, the molar ratio of iron to manganese in the metal precursor impregnation solution was 2:1, and the total mass of iron and manganese accounted for 5.5% of the mass of the pretreated activated carbon.

[0043] Pretreated activated carbon was immersed in a metal precursor impregnation solution and stirred continuously at room temperature for 2 hours, followed by standing at room temperature for 24 hours to allow metal ions to fully penetrate the micropores of the pretreated activated carbon, resulting in wet metal-loaded activated carbon. The wet metal-loaded activated carbon was placed in a constant-temperature drying oven and dried at 110℃ for 12 hours to completely remove internal free moisture. The dried metal-loaded activated carbon was placed in a tube furnace and heated to 500℃ at a rate of 5℃ per minute under continuous high-purity nitrogen as a protective gas. It was then calcined at 500℃ for 4 hours, and after calcination, it was naturally cooled to room temperature under a nitrogen protective atmosphere to obtain iron-manganese composite modified activated carbon.

[0044] Preparation Example 2: This preparation example provides a method for preparing iron and manganese composite modified activated carbon, including the following steps: 100 parts of coal-based columnar activated carbon were washed three times in ultrapure water to remove dust and impurities from the surface. They were then dried in a constant-temperature drying oven at 105℃ for 12 hours to obtain pretreated activated carbon. 10.9 parts of ferric nitrate nonahydrate and 9.7 parts of a 50% (w / w) manganese nitrate aqueous solution were weighed and mixed, then 100 parts of ultrapure water were added and stirred to dissolve, preparing a metal precursor impregnation solution. At this point, the molar ratio of iron to manganese in the metal precursor impregnation solution was 1:1, and the total mass of iron and manganese accounted for 3.0% of the mass of the pretreated activated carbon.

[0045] Pretreated activated carbon was immersed in a metal precursor impregnation solution and stirred continuously at room temperature for 2 hours, followed by standing at room temperature for 24 hours to allow metal ions to fully penetrate the micropores of the pretreated activated carbon, resulting in wet metal-loaded activated carbon. The wet metal-loaded activated carbon was placed in a constant-temperature drying oven and dried at 110℃ for 12 hours to completely remove internal free moisture. The dried metal-loaded activated carbon was placed in a tube furnace and heated to 450℃ at a rate of 5℃ per minute under continuous high-purity nitrogen as a protective gas. It was then calcined at 450℃ for 4 hours, and after calcination, it was naturally cooled to room temperature under a nitrogen protective atmosphere to obtain iron-manganese composite modified activated carbon.

[0046] Preparation Example 3: This preparation example provides a method for preparing iron-manganese composite modified activated carbon, including the following steps: 100 parts of coal-based columnar activated carbon are washed three times in ultrapure water to remove dust and impurities from the surface of the coal-based columnar activated carbon, and then placed in a constant temperature drying oven at 105℃ for 12 hours to obtain pretreated activated carbon. 43.5 parts of ferric nitrate nonahydrate and 12.8 parts of a 50% manganese nitrate aqueous solution are weighed and mixed, and 100 parts of ultrapure water are added and stirred to dissolve, preparing a metal precursor impregnation solution. At this time, the molar ratio of iron to manganese in the metal precursor impregnation solution is 3:1, and the total mass of iron and manganese accounts for 8.0% of the mass of the pretreated activated carbon.

[0047] Pretreated activated carbon was immersed in a metal precursor impregnation solution and stirred continuously at room temperature for 2 hours, followed by standing at room temperature for 24 hours to allow metal ions to fully penetrate the micropores of the pretreated activated carbon, resulting in wet metal-loaded activated carbon. The wet metal-loaded activated carbon was placed in a constant-temperature drying oven and dried at 110℃ for 12 hours to completely remove internal free moisture. The dried metal-loaded activated carbon was placed in a tube furnace and heated to 550℃ at a rate of 5℃ per minute under continuous high-purity nitrogen as a protective gas. It was then calcined at 550℃ for 4 hours, and after calcination, it was naturally cooled to room temperature under a nitrogen protective atmosphere to obtain iron-manganese composite modified activated carbon.

[0048] Examples 1-5: Example 1: This embodiment provides a waste gas delayed oxidation treatment process, including the following steps: The iron-manganese composite modified activated carbon prepared in Preparation Example 1 was packed into a sealed reaction chamber 200 to form an adsorption bed. The main inlet valve 103 and the main outlet valve 203 were opened, while the closed-loop circulation valve 401 remained closed. The initial concentration of 500 mg / m³ was increased to room temperature. 3The simulated waste gas is continuously introduced into the closed reaction chamber 200. The simulated waste gas passes through the iron and manganese composite modified activated carbon adsorption bed 201 and undergoes physical adsorption and enrichment until the iron and manganese composite modified activated carbon adsorption bed 201 reaches the adsorption saturation state, at which point the introduction of simulated waste gas is stopped.

[0049] The main intake valve 103 and main exhaust valve 203 are forcibly closed, the closed-loop circulation valve 401 is opened, and the variable frequency centrifugal main fan 300 is started. The ozone generator 504 and the electric heating vaporizer 503 are started, and the operating temperature of the electric heating vaporizer 503 is set to 50℃. The metering pump 502 is started to inject 30% hydrogen peroxide into the electric heating vaporizer 503, completely converting the liquid hydrogen peroxide into mixed steam. The mixed steam combines with the ozone generated by the ozone generator 504 and is blown into the sealed reaction chamber 200. The relative humidity inside the sealed reaction chamber 200 is monitored in real time using the temperature and humidity sensor group 202, and the injection amount of mixed steam is adjusted to stabilize the relative humidity inside the sealed reaction chamber 200 at 82%. This drives the oxidation medium to undergo capillary co-condensation inside the micropores of the iron and manganese composite modified activated carbon, forming a liquid-phase microreactor.

[0050] The variable frequency controller 301 drives the variable frequency centrifugal main fan 300 to perform pulse scouring. The system wind speed alternates between a low-frequency reference wind speed of 0.4 m / s and a high-frequency jump wind speed of 1.5 m / s, switching every 5 minutes. During the frequency alternation operation, the pressure relief valve 402 and the isobaric air supply valve 403 open momentarily every 10 minutes, discharging the enriched carbon dioxide while simultaneously replenishing an equal volume of fresh air. The in-situ delayed oxidation regeneration reaction continues for 120 minutes.

[0051] After the in-situ delayed oxidation and regeneration reaction is completed, close the closed-loop circulation valve 401, the electric heating vaporizer 503 and the ozone generator 504, and reopen the main inlet valve 103 and the main exhaust valve 203. Purge the iron and manganese composite modified activated carbon adsorption bed 201 into the sealed reaction chamber 200 with dry air for 60 minutes to complete the drying and reset of the system.

[0052] Example 2: This embodiment provides a waste gas delayed oxidation treatment process, including the following steps: The iron-manganese composite modified activated carbon prepared in Preparation Example 1 was packed into a sealed reaction chamber 200 to form an adsorption bed. The main inlet valve 103 and the main outlet valve 203 were opened, while the closed-loop circulation valve 401 remained closed. The initial concentration of 500 mg / m³ was increased to room temperature. 3 The simulated waste gas is continuously introduced into the closed reaction chamber 200. The simulated waste gas passes through the iron and manganese composite modified activated carbon adsorption bed 201 and undergoes physical adsorption and enrichment until the iron and manganese composite modified activated carbon adsorption bed 201 reaches the adsorption saturation state, at which point the introduction of simulated waste gas is stopped.

[0053] The main intake valve 103 and main exhaust valve 203 are forcibly closed, the closed-loop circulation valve 401 is opened, and the variable frequency centrifugal main fan 300 is started. The ozone generator 504 and the electric heating vaporizer 503 are started, and the operating temperature of the electric heating vaporizer 503 is set to 45℃. The metering pump 502 is started to inject 30% hydrogen peroxide into the electric heating vaporizer 503, completely converting the liquid hydrogen peroxide into mixed steam. The mixed steam combines with the ozone generated by the ozone generator 504 and is blown into the sealed reaction chamber 200. The relative humidity inside the sealed reaction chamber 200 is monitored in real time using the temperature and humidity sensor group 202, and the injection amount of mixed steam is adjusted to stabilize the relative humidity inside the sealed reaction chamber 200 at 80%. This drives the oxidation medium to undergo capillary co-condensation inside the micropores of the iron and manganese composite modified activated carbon, forming a liquid-phase microreactor.

[0054] The variable frequency controller 301 drives the variable frequency centrifugal main fan 300 to perform pulse scouring. The system wind speed alternates between a low-frequency reference wind speed of 0.4 m / s and a high-frequency jump wind speed of 1.2 m / s, switching every 5 minutes. During the frequency alternation operation, the pressure relief valve 402 and the isobaric air supply valve 403 open momentarily every 10 minutes, discharging the enriched carbon dioxide while simultaneously replenishing an equal volume of fresh air. The in-situ delayed oxidation regeneration reaction continues for 120 minutes.

[0055] After the in-situ delayed oxidation and regeneration reaction is completed, close the closed-loop circulation valve 401, the electric heating vaporizer 503 and the ozone generator 504, and reopen the main inlet valve 103 and the main exhaust valve 203. Purge the iron and manganese composite modified activated carbon adsorption bed 201 into the sealed reaction chamber 200 with dry air for 60 minutes to complete the drying and reset of the system.

[0056] Example 3: This embodiment provides a waste gas delayed oxidation treatment process, including the following steps: The iron-manganese composite modified activated carbon prepared in Preparation Example 1 was packed into a sealed reaction chamber 200 to form an adsorption bed. The main inlet valve 103 and the main outlet valve 203 were opened, while the closed-loop circulation valve 401 remained closed. The initial concentration of 500 mg / m³ was increased to room temperature. 3 The simulated waste gas is continuously introduced into the closed reaction chamber 200. The simulated waste gas passes through the iron and manganese composite modified activated carbon adsorption bed 201 and undergoes physical adsorption and enrichment until the iron and manganese composite modified activated carbon adsorption bed 201 reaches the adsorption saturation state, at which point the introduction of simulated waste gas is stopped.

[0057] Forcefully close the main intake valve 103 and the main exhaust valve 203, open the closed-loop circulation valve 401, and start the variable frequency centrifugal main fan 300. Start the ozone generator 504 and the electric heating vaporizer 503, set the operating temperature of the electric heating vaporizer 503 to 55℃, and start the metering pump 502 to inject 30% hydrogen peroxide into the electric heating vaporizer 503, completely converting the liquid hydrogen peroxide into mixed steam. The mixed steam and the ozone generated by the ozone generator 504 are then blown into the sealed reaction chamber 200.

[0058] The relative humidity inside the sealed reaction chamber 200 is monitored in real time by a temperature and humidity sensor group 202. The injection amount of mixed steam is adjusted to stabilize the relative humidity inside the sealed reaction chamber 200 at 85%. This drives the oxidation medium to undergo capillary co-condensation inside the micropores of the iron and manganese composite modified activated carbon, forming a liquid-phase microreactor. The variable frequency controller 301 drives the variable frequency centrifugal main fan 300 to perform pulse scouring. The system wind speed alternates between a low-frequency reference wind speed of 0.4 m / s and a high-frequency jump wind speed of 1.8 m / s, with the alternation frequency changing once every 5 minutes.

[0059] During the variable frequency alternating operation, the pressure relief valve 402 and the isobaric air supply valve 403 open momentarily every 10 minutes to discharge the enriched carbon dioxide while simultaneously replenishing an equal volume of fresh air. The in-situ delayed oxidation and regeneration reaction continues for 120 minutes. After the in-situ delayed oxidation and regeneration reaction is completed, the closed-loop circulation valve 401, the electrically heated vaporizer 503, and the ozone generator 504 are closed. The main intake valve 103 and the main exhaust valve 203 are reopened, and dry air is introduced into the sealed reaction chamber 200 to purge the iron and manganese composite modified activated carbon adsorption bed 201 for 60 minutes, completing the system's drying and reset process.

[0060] Example 4: This embodiment provides a waste gas delayed oxidation treatment process, including the following steps: The iron-manganese composite modified activated carbon prepared in Preparation Example 2 was packed into a sealed reaction chamber 200 to form an adsorption bed. The main inlet valve 103 and the main outlet valve 203 were opened, while the closed-loop circulation valve 401 remained closed. The initial concentration of 500 mg / m³ was increased to room temperature. 3 The simulated waste gas is continuously introduced into the closed reaction chamber 200. The simulated waste gas passes through the iron and manganese composite modified activated carbon adsorption bed 201 and undergoes physical adsorption and enrichment until the iron and manganese composite modified activated carbon adsorption bed 201 reaches the adsorption saturation state, at which point the introduction of simulated waste gas is stopped.

[0061] Forcefully close the main intake valve 103 and the main exhaust valve 203, open the closed-loop circulation valve 401, and start the variable frequency centrifugal main fan 300. Start the ozone generator 504 and the electric heating vaporizer 503, set the working temperature of the electric heating vaporizer 503 to 50°C, and start the metering pump 502 to inject 30% hydrogen peroxide into the electric heating vaporizer 503, completely converting the liquid hydrogen peroxide into mixed steam. The mixed steam and the ozone generated by the ozone generator 504 are then blown into the sealed reaction chamber 200.

[0062] The relative humidity inside the sealed reaction chamber 200 is monitored in real time by a temperature and humidity sensor group 202. The injection amount of mixed steam is adjusted to stabilize the relative humidity inside the sealed reaction chamber 200 at 82%. This drives the oxidation medium to undergo capillary co-condensation inside the micropores of the iron and manganese composite modified activated carbon, forming a liquid-phase microreactor. The variable frequency controller 301 drives the variable frequency centrifugal main fan 300 to perform pulse scouring. The system wind speed alternates between a low-frequency reference wind speed of 0.4 m / s and a high-frequency jump wind speed of 1.5 m / s, with the alternation frequency occurring once every 5 minutes.

[0063] During the variable frequency alternating operation, the pressure relief valve 402 and the isobaric air supply valve 403 open momentarily every 10 minutes to discharge the enriched carbon dioxide while simultaneously replenishing an equal volume of fresh air. The in-situ delayed oxidation and regeneration reaction continues for 120 minutes. After the in-situ delayed oxidation and regeneration reaction is completed, the closed-loop circulation valve 401, the electrically heated vaporizer 503, and the ozone generator 504 are closed. The main intake valve 103 and the main exhaust valve 203 are reopened, and dry air is introduced into the sealed reaction chamber 200 to purge the iron and manganese composite modified activated carbon adsorption bed 201 for 60 minutes, completing the system's drying and reset process.

[0064] Example 5: This embodiment provides a waste gas delayed oxidation treatment process, including the following steps: The iron-manganese composite modified activated carbon prepared in Preparation Example 3 was packed into a sealed reaction chamber 200 to form an adsorption bed. The main inlet valve 103 and the main outlet valve 203 were opened, while the closed-loop circulation valve 401 remained closed. The initial concentration of 500 mg / m³ was set at room temperature. 3 The simulated waste gas is continuously introduced into the closed reaction chamber 200. The simulated waste gas passes through the iron and manganese composite modified activated carbon adsorption bed 201 and is adsorbed and enriched until the iron and manganese composite modified activated carbon adsorption bed 201 reaches the adsorption saturation state, at which point the introduction of simulated waste gas is stopped.

[0065] The main intake valve 103 and main exhaust valve 203 are forcibly closed, the closed-loop circulation valve 401 is opened, and the variable frequency centrifugal main fan 300 is started. The ozone generator 504 and the electric heating vaporizer 503 are started, and the operating temperature of the electric heating vaporizer 503 is set to 50℃. The metering pump 502 is started to inject 30% hydrogen peroxide into the electric heating vaporizer 503, completely converting the liquid hydrogen peroxide into mixed steam. The mixed steam combines with the ozone generated by the ozone generator 504 and is blown into the sealed reaction chamber 200. The relative humidity inside the sealed reaction chamber 200 is monitored in real time using the temperature and humidity sensor group 202, and the injection amount of mixed steam is adjusted to stabilize the relative humidity inside the sealed reaction chamber 200 at 82%. This drives the oxidation medium to undergo capillary co-condensation inside the micropores of the iron and manganese composite modified activated carbon, forming a liquid-phase microreactor. The variable frequency controller 301 drives the variable frequency centrifugal main fan 300 to perform pulse scouring. The system wind speed alternates between a low-frequency reference wind speed of 0.4 m / s and a high-frequency jump wind speed of 1.5 m / s, with the alternation switching frequency being once every 5 minutes.

[0066] During the variable frequency alternating operation, the pressure relief valve 402 and the isobaric air supply valve 403 open momentarily every 10 minutes to discharge the enriched carbon dioxide while simultaneously replenishing an equal volume of fresh air. The in-situ delayed oxidation and regeneration reaction continues for 120 minutes. After the in-situ delayed oxidation and regeneration reaction is completed, the closed-loop circulation valve 401, the electrically heated vaporizer 503, and the ozone generator 504 are closed. The main intake valve 103 and the main exhaust valve 203 are reopened, and dry air is introduced into the sealed reaction chamber 200 to purge the iron and manganese composite modified activated carbon adsorption bed 201 for 60 minutes, completing the system's drying and reset process.

[0067] Comparative Examples 1-5: Comparative Example 1: Compared with Example 1, the differences are as follows: the iron and manganese composite modified activated carbon prepared in Example 1 was not used, but unmodified ordinary coal-based columnar activated carbon was used to form the adsorption bed; the electric heating vaporizer 503 and metering pump 502 were not started during the in-situ delayed oxidation regeneration reaction, and hydrogen peroxide mixed steam was not injected, only ozone was continuously introduced; the relative humidity inside the sealed reaction chamber 200 was not controlled; the variable frequency centrifugal main fan 300 always maintained a constant wind speed of 0.4 m / s, without high-frequency sudden wind speed pulse scouring, and the rest were the same.

[0068] Comparative Example 2: Compared with Example 1, the difference is that during the in-situ delayed oxidation regeneration reaction, the injection amount of mixed steam is adjusted to keep the relative humidity inside the sealed reaction chamber 200 at only 50%, while the rest are the same.

[0069] Comparative Example 3: Compared with Example 1, the difference is that during the in-situ delayed oxidation regeneration reaction, the variable frequency controller 301 drives the variable frequency centrifugal main fan 300 to always run at a constant wind speed of 0.4 m / s, and does not perform high-frequency sudden wind speed alternation switching, while the rest are the same.

[0070] Comparative Example 4: Compared with Example 1, the difference is that instead of using an electric heating vaporizer 503 to convert liquid hydrogen peroxide into mixed steam, an ultrasonic atomizer is used to atomize liquid hydrogen peroxide into micron-sized droplets and then spray them directly into the sealed reaction chamber 200. All other aspects are the same.

[0071] Comparative Example 5: Compared to Example 1, the difference lies in that the adsorption bed inside the sealed reaction chamber 200 is filled with ferric modified activated carbon instead of the iron and manganese composite modified activated carbon prepared in Example 1. The ferric modified activated carbon is prepared using an impregnation solution containing only ferric nitrate nonahydrate and no manganese nitrate; all other aspects are the same.

[0072] Test Examples 1-5: Test Example 1: Feasibility Test of Macroscopic Balance and Capillary Co-condensation in Liquid-Phase Microreactors Prepare test systems and adsorption beds corresponding to Examples 1, 2, 3, 2, and 4, and weigh the initial mass of the iron and manganese composite modified activated carbon or ordinary coal-based columnar activated carbon adsorption bed before loading each test system.

[0073] The weighed adsorption bed is then filled into the corresponding sealed reaction chamber 200. A sealed liquid collector equipped with a high-precision weighing sensor is connected to the bottom of the sealed reaction chamber 200 to collect and measure in real time the free liquid that has not entered the micropores but has condensed and accumulated on the external surface.

[0074] Each test system was started, and the in-situ delayed oxidation and regeneration reaction steps were strictly executed according to the process parameters set in Examples 1, 2, and 3, as well as Comparative Examples 2 and 4. During the 120-minute reaction cycle, the total mass of liquid hydrogen peroxide injected into the sealed reaction chamber 200 was recorded using the microfluidic metering pump 502. The recorded total mass of liquid hydrogen peroxide, plus the converted value of the air-based moisture content introduced into the system, was defined as the total input mass of the system.

[0075] After the in-situ delayed oxidation regeneration reaction has run for 120 minutes, the gas supply valve is immediately shut off, and the adsorption bed is removed entirely from the sealed reaction chamber 200. Within one minute, the total wet mass of the adsorption bed is weighed on an industrial electronic balance. The mass increment of the adsorption bed is obtained by subtracting the initial mass of the adsorption bed from the total wet mass.

[0076] Read the value displayed on the sealed liquid collector at the bottom of the 200-ton closed reaction chamber and record it as the mass of the free liquid discharged from the bottom. Divide the mass increment of the adsorption bed by the total input mass of the system to obtain the micropore retention rate of the medium. Integrate all test data.

[0077] Table 1. Test data on macroscopic mass balance and capillary co-condensation characteristics of the oxidation medium. Conclusion: Based on Table 1 and Figure 2 The data shows that when the relative humidity was set between 80% and 85%, the mass increments of the adsorption bed in Examples 1, 2, and 3 were 147.61 g, 138.42 g, and 154.23 g, respectively. Table 1 shows that the increments accounted for the majority of the total input mass of the system. Figure 2 The line graph shows that the micropore retention rate of the medium ranges from 95.34% to 96.89%. Meanwhile, the bottom free liquid mass of the three test groups was 0 g or 1.14 g. The data distribution indicates that the gaseous hydrogen peroxide and water molecules input into the system did not condense over a large area outside the bed, but instead successfully penetrated the macroscopic channels of the activated carbon and remained there. This suggests that under the set high humidity conditions, the gaseous medium underwent a phase change upon entering the micropores and remained within the microscopic channels, forming the required liquid environment.

[0078] Combined with Table 1 Figure 2 Observing Comparative Example 2, when the relative humidity was set to 50%, the micropore retention rate of the medium dropped to 14.05%, and the mass increment of the adsorption bed was only 12.15g. The data shows that when the relative humidity of the system is lower than the threshold condition required for the medium to condense, most of the hydrogen peroxide and water molecules input into the system are directly discharged from the system in the form of gas phase with the tail gas and fail to be enriched in the micropores of activated carbon. The test results of the comparative example show that controlling the relative humidity above 80% is a necessary prerequisite for realizing the phase change of the medium inside the micropores and constructing a liquid phase reactor.

[0079] from Figure 2 The bar chart provides a clear comparison. In Comparative Example 4, which uses ultrasonic atomization to directly spray liquid hydrogen peroxide into the system, the mass of the free liquid discharged from the bottom reached 88.51g, the mass increase of the adsorption bed was 53.27g, and the micropore retention rate of the medium was only 35.54%. This indicates that the large-diameter droplets generated by atomization accumulated upon contact with the outer surface of the adsorption bed, forming an aqueous phase layer that hindered the transport of the medium to the internal micropores. Excess liquid settled and was discharged along the inner wall of the equipment, demonstrating that direct spraying of droplets would cause external liquid phase blockage. In this example, the step of converting the liquid medium into vapor input through electric heating avoids the problem of external channel blockage by the liquid phase, allowing the medium to penetrate the outer surface of the bed in the form of gas molecules and then condense inside the micropores.

[0080] Test Example 2: Dynamic Verification Test of Mass Transfer Gas Seal Breaking by Variable Frequency Shear Flow The iron and manganese composite modified activated carbon adsorption beds 201 specified in Examples 1, 2, 3 and Comparative Example 3 under the adsorption saturation state were selected and filled into the corresponding sealed reaction chambers 200.

[0081] High-precision micro-differential pressure transmitters are installed on the inlet and outlet sides of the adsorption bed inside the sealed reaction chamber 200, and a high-frequency infrared carbon dioxide gas analyzer is installed inside the outlet pipe of the pressure relief valve 402. These sensors are connected to a data acquisition terminal, and the sampling frequency for differential pressure and carbon dioxide concentration is set to once per second.

[0082] The system is started to execute the in-situ delayed oxidation and regeneration reaction. The variable frequency centrifugal main fan 300 in Examples 1, 2 and 3 operates alternately according to their respective set low-frequency reference wind speed and high-frequency sudden wind speed parameters; the variable frequency centrifugal main fan 300 in Comparative Example 3 always maintains a constant wind speed of 0.4 m / s.

[0083] The test system ran continuously for 120 minutes. The period from the 60th to the 70th minute of the regeneration reaction was designated as the stable test segment. The maximum pressure difference of the bed and the instantaneous peak concentration of exhaust carbon dioxide at the moment of high-frequency sudden wind speed triggering or during the exhaust process were extracted from the data acquisition terminal. The total cumulative carbon dioxide emissions within this 10-minute interval were calculated by integration. All data were recorded and summarized.

[0084] Table 2. Test data on bed pressure drop and dynamic carbon dioxide emissions during the mid-term regeneration reaction. Conclusion: Based on Table 2 and Figure 3 According to the data, in Examples 1, 2, and 3, when operating with alternating high and low frequency wind speeds, the maximum bed pressure differences measured were 1456 Pa, 1124 Pa, and 1768 Pa, respectively. Figure 3 The bar chart on the left axis visually shows that the pressure difference data for these three groups is higher than the 412 Pa of Comparative Example 3, which operates at constant wind speed. Figure 3 The line graph on the right axis shows that the instantaneous peak concentration of exhaust carbon dioxide in Examples 1 to 3 reached 8742 mg / m³, respectively. 3 7218mg / m 3 and 8953mg / m 3 The pressure difference rise phase is accompanied by the discharge of high concentrations of carbon dioxide, reflecting that the sudden change in wind speed caused by the frequency conversion operation generates pressure disturbance in the pores of the adsorption bed, which in turn squeezes out the carbon dioxide gas trapped in the micropores, indicating that the alternating wind speed of the frequency conversion can strip the gas in the pores.

[0085] When the main fan maintains a constant wind speed of 0.4 m / s, not only Figure 3 The maximum pressure differential in the bed remained relatively low at 412 Pa, and the instantaneous peak concentration of carbon dioxide was only 2145 mg / m³. 3 Since no additional pressure difference is generated inside the system due to changes in wind speed, the smoothly penetrating airflow cannot reach the inside of the micropores, causing some of the carbon dioxide generated by the reaction to remain inside the activated carbon particles. The lack of airflow shear disturbance makes it difficult for the byproduct gas in the pores to be discharged.

[0086] The cumulative carbon dioxide emissions in Examples 1, 2, and 3 over a 10-minute interval were 321.4 mg, 289.6 mg, and 335.2 mg, respectively, while the cumulative emissions in Comparative Example 3 were 114.8 mg. Since carbon dioxide is a mineralized oxidation product of pollutants, the emission amount can be used as a reference indicator for the continuity of the system reaction. The low cumulative amount in Comparative Example 3 indicates that the unexpelled gas occupies volume in the micropores, hindering the subsequent entry of hydrogen peroxide and ozone into the micropores for replenishment and consumption, thus slowing down the reaction within the micropores. The examples utilized alternating wind speeds to expel more gaseous products, reducing the gas volume occupied in the micropores and ensuring that the external oxidation medium can continuously diffuse inward and participate in the oxidation reaction.

[0087] Test Example 3: Bed Isothermal Thermodynamic Verification Test of In-situ Delayed Oxidation System Prepare the test system and the sealed reaction chamber 200 filled with the adsorption bed specified in Examples 1, 2, and 3, as well as Comparative Examples 1 and 2, which are in an adsorption saturation state.

[0088] Three sets of K-type thermocouple temperature sensors are pre-embedded in the adsorption bed inside each sealed reaction chamber 200. The installation positions of the three sets of thermocouple temperature sensors are respectively located at the center of the air inlet side section, the geometric center of the adsorption bed, and the center of the air outlet side section of the adsorption bed. All thermocouple temperature sensors are connected to a multi-channel temperature monitoring instrument, and the temperature data recording frequency is set to be once every 30 seconds.

[0089] Start the variable frequency centrifugal main fan 300 and the matching oxidation medium injection equipment, and perform the in-situ delayed oxidation regeneration reaction steps according to the relative humidity, wind speed parameters and oxidant ratio conditions set in Examples 1, 2, 3 and Comparative Examples 1 and 2.

[0090] The test system ran continuously for 120 minutes. Throughout the entire in-situ delayed oxidation and regeneration reaction, a multi-channel temperature monitoring instrument recorded the dynamic temperature changes at three measurement points in real time. After the reaction, the differences between the highest temperatures recorded during the reaction at the inlet side, center point, and outlet side and the initial reaction start temperature were extracted and calculated. The calculated differences were defined as the local maximum temperature rise. Temperature data from all test groups were summarized and organized.

[0091] Table 3. Dynamic temperature rise test data of the bed at multiple points during the oxidation regeneration reaction. Conclusion: Based on Table 3 and Figure 4 According to the data, during the in-situ delayed oxidation reaction in Examples 1, 2 and 3, the maximum temperature rise on the intake side was between 1.8°C and 2.5°C, the maximum temperature rise at the center point was between 3.1°C and 4.1°C, and the maximum temperature rise on the outlet side was between 2.4°C and 2.9°C. Figure 4 The right-axis line graph shows that the overall average temperature rise of the bed in Examples 1, 2 and 3 remained at a low level of 2.4°C to 3.2°C. The oxidation process of organic matter releases heat, but under high relative humidity conditions, the input water condenses and accumulates inside the micropores of activated carbon to form liquid water.

[0092] When the reaction is exothermic, the liquid water inside the micropores vaporizes and absorbs the heat generated by the reaction. The vaporized water vapor is then discharged from the system by the airflow from the fan, completing the heat transfer to the outside. This demonstrates that the temperature fluctuation of the adsorption bed can be controlled within a small range through the phase change endothermic mechanism.

[0093] Comparative Example 1 uses a method of introducing pure ozone without controlling humidity, from Figure 4 The bar chart shows that in Comparative Example 1, the highest temperature rise on the inlet side reached 15.6℃, the highest temperature rise at the center point reached 42.3℃, and the highest temperature rise on the outlet side was 28.7℃. Under dry-state reaction conditions without the participation of liquid water phase change endothermic reaction, the heat released by the reaction can only be carried away by gas flow. Due to the low specific heat capacity of the gas and the limited flow rate, the heat could not be discharged in time. Figure 4 The gray column in the middle is significantly higher than the columns on both sides, indicating that the central area of ​​the adsorption bed is far from the external heat dissipation surface, resulting in a significant internal heat accumulation and a higher central temperature.

[0094] Observing the test data of Comparative Example 2 in Table 3, when the relative humidity is set to 50%, the highest temperature on the intake side rises to 8.4℃, and the highest temperature at the center point rises to 19.5℃. Figure 4The line graph shows that the overall average temperature rise was 13.3℃. When the relative humidity was 50%, the conditions for a large amount of capillary condensation of the medium in the activated carbon channels were not met. The amount of liquid water retained in the micropores was limited. In the early stage of the reaction, a small amount of water evaporated and absorbed heat, but after the water was exhausted, the subsequent exothermic reaction lacked the buffer of the phase change endothermic medium, which led to an increase in bed temperature. The temperature data of the comparative example confirms that controlling the relative humidity above 80% to ensure that there is sufficient liquid phase material in the micropores is a necessary process condition for achieving isothermal reaction in the bed.

[0095] Test Example 4: Comparison Test of Overall Degradation Rate and Deep Mineralization Rate of Exhaust Gas The catalyst materials prepared for Examples 1, 2, and 3, as well as Comparative Examples 1, 2, and 5, were respectively filled into independent sealed reaction chambers 200 to construct adsorption beds, with a concentration of 500 mg / m³. 3 Toluene was used as a standard volatile organic compound to simulate waste gas. The airflow temperature was controlled at 25℃, and the simulated waste gas was continuously introduced into each closed reaction chamber 200 until the toluene concentration at the exhaust end was equal to the inlet concentration. It was then determined that the adsorption bed had reached adsorption saturation. The initial total adsorption capacity of each adsorption bed was calculated and recorded by integrating the airflow rate and the concentration difference before and after adsorption.

[0096] Cut off the simulated waste gas source, seal off each reaction system, and start the variable frequency fan and reagent injection equipment according to the operating parameters, temperature and humidity conditions and oxidation medium addition methods corresponding to Examples 1, 2, 3 and Comparative Examples 1, 2 and 5, respectively, to carry out an in-situ delayed oxidation regeneration reaction for 120 minutes.

[0097] During the regeneration reaction and the subsequent 60-minute drying and purging phase, all exhaust gases from the system were collected. The exhaust gases were then connected to a high-precision gas chromatograph and an infrared carbon-sulfur analyzer to continuously detect the total amount of residual gaseous toluene and the cumulative emissions of carbon dioxide generated in the reaction.

[0098] After the entire test procedure was completed, the adsorption bed inside the sealed reaction chamber 200 was removed, and the used catalytic adsorption material was ultrasonically extracted using dichloromethane solvent. The extract was injected into a gas chromatograph for quantitative analysis to determine the total amount of undegraded toluene remaining in the solid phase inside the adsorption bed.

[0099] The total amount of residual gaseous toluene in the exhaust gas is added to the total amount of undegraded toluene remaining in the solid phase to obtain the total amount of residual undegraded volatile organic compounds. The overall degradation rate is calculated by subtracting the total amount of residual undegraded toluene from the initial total adsorption amount and then dividing by the initial total adsorption amount. Based on the stoichiometric ratio of carbon dioxide produced by the complete combustion of toluene, the theoretical maximum carbon dioxide production for each group is calculated. The deep mineralization rate is calculated by dividing the actual measured cumulative carbon dioxide emissions by the theoretical maximum carbon dioxide production.

[0100] Table 4. Test data on comprehensive degradation rate and deep mineralization rate of waste gas Conclusion: Based on Table 4 and Figure 5 The data shows that the overall degradation rate of Examples 1, 2, and 3 ranged from 96.95% to 97.82%, with deep mineralization rates reaching 91.21%, 88.39%, and 90.41%, respectively. Figure 5 The line graph on the right shows that the actual residual undegraded total amount remains at a low level of 98.1 mg to 136.5 mg. The data indicates that under high relative humidity conditions, hydrogen peroxide and ozone react in the liquid phase environment formed by condensation inside the micropores of activated carbon, producing hydroxyl radicals with strong oxidizing power. The liquid phase oxidation process can destroy the structure of the adsorbed toluene molecules and convert them into carbon dioxide and water, rather than remaining in the intermediate reaction stage.

[0101] Combined with Table 4 Figure 5 The data in Comparative Example 1 were obtained using a pure ozone oxidation method without humidity control. Figure 5 The line graph shows that the total amount of undegraded residue in Comparative Example 1 reached 1756.2 mg. The bar chart on the left shows that the comprehensive degradation rate and deep mineralization rate of Comparative Example 1 were only 61.02% and 34.19%, respectively. When gaseous ozone comes into direct contact with organic matter adsorbed on the solid surface, due to the limitation of mass transfer between the gas and solid phases and the fact that the direct oxidation potential of ozone molecules is lower than that of hydroxyl radicals, the pollutants cannot be completely converted into carbon dioxide gas and discharged.

[0102] As can be seen from the test results of Comparative Example 2 in Table 4, when the system relative humidity is set to 50%, the overall degradation rate is 74.50% and the deep mineralization rate is 48.37%. Figure 5 The line graph shows that the residual amount is 1145.3 mg. Since the humidity of 50% does not meet the conditions required for capillary condensation inside the micropores, the system lacks continuous liquid water. The lack of liquid phase medium makes it difficult for ozone and hydrogen peroxide to be efficiently converted into hydroxyl radicals. The oxidation reaction inside the system mainly relies on the molecular medium, which reduces the overall deep mineralization capacity.

[0103] Comparative analysis of Table 4 and Figure 5According to the data from Comparative Example 5, when using single-iron modified activated carbon instead of iron and manganese composite modified activated carbon, the overall degradation rate was 86.67%, but... Figure 5 The light gray bar chart shows that the deep mineralization rate decreased to 62.25%, and the line graph shows that the total amount of residual undegraded substances was 584.6 mg. In the Fenton-like reaction, after iron ions are oxidized to a high valence state, their reduction to a low valence state is slow. The lack of manganese ions results in an incomplete electron transfer pathway within the catalyst, hindering the recycling and regeneration of iron ions. The inability of active sites to recover quickly leads to a decrease in the yield of hydroxyl radicals over time, and the oxidation process of organic matter stalls at the stage of generating intermediate products. The test group in the example maintained the continuity of the catalytic cycle and improved the final mineralization rate through the bimetallic synergistic configuration of iron and manganese.

[0104] Test Example 5: Comparison Test of Passivation Resistance and Long-Term Cycle Regeneration Life Prepare iron-manganese composite modified activated carbon or corresponding materials as specified in Examples 1, 2, 3, and Comparative Examples 3 and 4, and determine the initial iodine adsorption value of each material before use according to national standard methods. Fill the corresponding sealed reaction chambers 200 to form adsorption beds.

[0105] Standard adsorption test conditions were set, with an introduced concentration of 600 mg / m³. 3 The toluene-simulated waste gas was used, with the inlet temperature maintained at 25℃ and the apparent gas flow rate controlled at 0.5m / s. An online volatile organic compound concentration detector was installed at the exhaust end of the adsorption bed.

[0106] Open the simulated exhaust gas inlet valve and perform the first cycle adsorption phase test. Record the toluene concentration from the start of ventilation until it reaches 10% of the inlet concentration (i.e., 60 mg / m³). 3 The time elapsed is recorded as the time of the first cycle penetration.

[0107] After the first cycle adsorption stage, the simulated waste gas source is cut off, and the regeneration operation is performed according to the in-situ delayed oxidation regeneration process parameters set in Examples 1, 2, 3, 3, 3, and 4, including media injection, variable frequency or constant wind speed operation, and reaction time control. After the regeneration is completed, the drying and purging steps are performed to complete one complete adsorption and regeneration cycle.

[0108] Repeat the above adsorption and regeneration cycle until the system completes the 20th cycle. During the adsorption phase of the 20th cycle, record the toluene concentration again to reach 60 mg / m³. 3The time elapsed is recorded as the 20th cycle penetration time. The penetration time reduction rate is calculated by dividing the difference between the 1st cycle penetration time and the 20th cycle penetration time by the 1st cycle penetration time.

[0109] After the 20th cycle was completed, the adsorption bed materials of each group were unloaded from the sealed reaction chamber 200. After the removed materials were thoroughly dried, the iodine adsorption value of the materials after 20 cycles was measured again and recorded as the iodine adsorption value after the 20th cycle. The iodine adsorption value after the 20th cycle was divided by the initial iodine adsorption value before use to calculate the iodine retention rate. All recorded operating data and calculation results were summarized.

[0110] Table 5. Data on passivation resistance and lifetime of adsorption bed under long-term cyclic operation. Conclusion: Based on the data in Table 5, after 20 adsorption-regeneration cycles in Examples 1, 2, and 3, the breakthrough time of the 20th cycle ranged from 11.3 h to 11.9 h. Figure 6 As shown in the bar chart on the left, the height difference between the dark gray and light gray bars in the three test groups is small, and the corresponding penetration time reduction rate in Table 5 is 4.8% to 6.6%. Figure 6 The line graph on the right shows that the iodine retention rates of Examples 1 to 3 ranged from 90.7% to 93.2%. The test data demonstrates that the gas-phase mass transfer combined with variable frequency fan speed operation maintained the unobstructed flow of the internal pores of the adsorbent material. The fluid shear force generated by the variable frequency fan speed carried the carbon dioxide generated inside the micropores out of the system, preventing byproducts from occupying the pore space and maintaining the macroscopic adsorption capacity of the activated carbon material.

[0111] Observing the data of Comparative Example 3 in Table 5, this group adopted a constant wind speed operation process. After 20 cycles, the penetration time of the 20th cycle decreased to 6.5 hours. Figure 6 The bar chart on the left visually reflects the significant difference in penetration time between the two trials in Comparative Example 3. Table 5 calculates that the penetration time reduction rate is 46.7%. Figure 6 The line graph on the right shows that its iodine retention rate is 51.1%. Due to the limited airflow disturbance generated by the constant low wind speed, the gaseous products inside the micropores cannot be completely discharged. The bubbles that are not discharged in time hinder the oxidation reaction, resulting in some incompletely degraded organic intermediate products remaining inside the micropores. The solid or liquid phase residues inside the channels occupy the effective physical space, causing the adsorption performance of the material to decline after multiple cycles.

[0112] Combined with Table 5 and Figure 6Analyzing the test results of Comparative Example 4, which used ultrasonic atomization to directly spray liquid hydrogen peroxide into the system, after 20 cycles, Table 5 shows that the penetration time in the 20th cycle was 5.1 hours, and the penetration time reduction rate calculated in Table 5 reached 57.1%. Figure 6 The line graph reflects that its iodine retention rate decreased to 40.4%. When droplet-shaped hydrogen peroxide contacts the outer surface of activated carbon, it accumulates to form a liquid film, sealing the external pores. This external liquid film not only cuts off the escape path of internal carbon dioxide gas but also blocks the diffusion of fresh oxidizing medium inward. External sealing leads to the accumulation of reaction byproducts on the particle surface and causes pore blockage, reducing the effective pore volume of the material. The embodiment employs a mass transfer route of first vaporizing and then condensing inside the micropores, avoiding the problem of external liquid film blockage.

Claims

1. A method for room temperature delayed oxidation treatment of furniture spraying exhaust gas, characterized in that, Includes the following steps: The exhaust gas from furniture spraying is introduced into a reaction chamber (200) filled with an iron and manganese composite modified activated carbon adsorption bed (201) for physical adsorption and enrichment until the adsorption is saturated and then the gas is stopped. The reaction chamber (200) is isolated from the outside world and a closed-loop gas circuit is opened. The hydrogen peroxide aqueous solution is vaporized into mixed steam and then mixed with ozone and blown into the interior of the reaction chamber (200). The injection amount of the mixed steam is adjusted in conjunction with the real-time humidity monitoring, driving the oxidation medium composed of the mixed steam and the ozone to undergo capillary co-condensation inside the micropores of the iron and manganese composite modified activated carbon, and carrying out an in-situ delayed oxidation and regeneration reaction. Pulse flushing is performed in the closed-loop recirculating air circuit, alternating between low-frequency reference wind speed and high-frequency jump wind speed; During the alternating operation of the variable frequency, the enriched carbon dioxide gas is discharged to the outside while an equal volume of fresh air is replenished. After the in-situ delayed oxidation and regeneration reaction is completed, the injection of the hydrogen peroxide aqueous solution and the ozone is stopped, and the closed-loop circulation gas path is closed. Dry air is introduced into the reaction chamber (200) to purge the iron and manganese composite modified activated carbon adsorption bed (201) for system drying and reset.

2. The method for room temperature delayed oxidation treatment of furniture spraying exhaust gas according to claim 1, characterized in that, The preparation steps of the iron and manganese composite modified activated carbon specifically include: Washed and dried coal-based columnar activated carbon is immersed in a metal precursor impregnation solution containing ferric nitrate nonahydrate and a 50% (w / w) manganese nitrate aqueous solution. The mixture is stirred and allowed to stand for impregnation to obtain wet metal-supported activated carbon. After being dried at a constant temperature, the activated carbon is placed under a protective atmosphere and heated to 450°C–550°C at a heating rate of 5°C per minute for constant temperature calcination. The activated carbon is then naturally cooled to room temperature to obtain the iron-manganese composite modified activated carbon. The molar ratio of iron to manganese in the metal precursor impregnation solution is 1:1 to 3:1, and the total mass of iron and manganese accounts for 3%–8% of the mass of the dried coal-based columnar activated carbon.

3. The method for room temperature delayed oxidation treatment of furniture spraying exhaust gas according to claim 1, characterized in that, The hydrogen peroxide aqueous solution is 30% by mass; the vaporization working temperature is set to 45℃~55℃; the injection amount of the mixed steam is adjusted to keep the relative humidity inside the reaction chamber stable between 80% and 85%.

4. The method for room temperature delayed oxidation treatment of furniture spraying exhaust gas according to claim 1, characterized in that, The low-frequency reference wind speed is 0.4 m / s, the high-frequency jump wind speed is 1.2 m / s to 1.8 m / s, and the wind speed alternates every 5 minutes.

5. The method for room temperature delayed oxidation treatment of furniture spraying exhaust gas according to claim 1, characterized in that, During the frequency conversion alternating operation, the enriched carbon dioxide gas is momentarily discharged outward in a small amount every 10 minutes, while an equal volume of fresh air is replenished; the in-situ delayed oxidation regeneration reaction continues for 120 minutes, and dry air is introduced to purge for 60 minutes when the system is dried and reset.

6. A room temperature delayed oxidation treatment device for furniture spraying exhaust gas, characterized in that, A room temperature delayed oxidation treatment method for furniture spraying exhaust gas according to any one of claims 1-5, comprising: a pretreatment and air intake module, a core reaction and detection module, a power closed-loop circulation and exhaust control module, and an oxidation medium vaporization injection module; The output of the pretreatment and air intake module is connected to the air intake of the core reaction and detection module, which is used to intercept and humidify the furniture spraying exhaust gas and send it to the core reaction and detection module. The core reaction and detection module is used to provide a closed space for the adsorption, enrichment and delayed oxidation micro-reaction of waste gas and to monitor the internal temperature and humidity in real time. The closed-loop circulation and exhaust control module is connected to the exhaust side of the core reaction and detection module. It is used to provide fluid transport power to the system and to control the flow and pressure balance between the closed-loop circulation pipeline and the external exhaust. The output end of the oxidation medium vaporization injection module is connected to the end of the closed-loop circulation pipeline of the power closed-loop circulation and exhaust control module, and is used to mix the vaporized hydrogen peroxide mixed vapor with ozone and send it into the core reaction and detection module.

7. The ambient temperature delayed oxidation treatment device for furniture spraying exhaust gas according to claim 6, characterized in that, The pretreatment and air intake module includes an exhaust gas inlet pipe. A fresh air mixing valve (101) is installed at the front end of the exhaust gas inlet pipe. A dry filter (102) is installed on the downstream pipe of the fresh air mixing valve (101). The dry filter (102) is filled with multi-stage glass fiber filter cotton. An air intake main valve (103) is connected in series at the outlet end of the dry filter (102). The output end of the air intake main valve (103) is directly connected to the air intake of the core reaction and detection module.

8. The ambient temperature delayed oxidation treatment device for furniture spraying exhaust gas according to claim 6, characterized in that, The core reaction and detection module includes a sealed reaction chamber (200). Inside the sealed reaction chamber (200), a horizontal frame is provided with an iron and manganese composite modified activated carbon adsorption bed (201) with a thickness of 0.4m to 0.8m. A temperature and humidity sensor group (202) is inserted inside the sealed reaction chamber (200). The probes of the temperature and humidity sensor group (202) are respectively arranged at the bottom of the air inlet side and the top of the air outlet side of the iron and manganese composite modified activated carbon adsorption bed (201). An exhaust main valve (203) is installed at the top air outlet of the sealed reaction chamber (200).

9. The ambient temperature delayed oxidation treatment device for furniture spraying exhaust gas according to claim 6, characterized in that, The power closed-loop circulation and exhaust control module includes a variable frequency centrifugal main fan (300), which is located on the main pipeline on the exhaust side of the system and connected to a variable frequency controller (301). One end of the closed-loop circulation pipeline is connected between the outlet of the variable frequency centrifugal main fan (300) and the standard emission port (302), and the other end is connected back to the pipe section in front of the air inlet of the core reaction and detection module. A closed-loop circulation valve (401) is provided on the closed-loop circulation pipeline. A pressure relief exhaust valve (402) facing the external environment and an equal pressure replenishment valve (403) are also connected in parallel on the closed-loop circulation pipeline.

10. The ambient temperature delayed oxidation treatment device for furniture spraying exhaust gas according to claim 6, characterized in that, The oxidation medium vaporization injection module includes a hydrogen peroxide storage tank (501), a metering pump (502), and an electric heating vaporizer (503) with closed-loop temperature control connected in sequence, and is equipped with an ozone generator (504) using surface discharge technology. The gas phase outlet of the electric heating vaporizer (503) and the gas outlet pipeline of the ozone generator (504) are connected to the end of the closed-loop circulation pipeline, and the connection point is close to the air inlet of the core reaction and detection module.

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