A system for simultaneous removal of hydrogen sulfide and phosphine and a method thereof

Abstract

This invention provides a novel system and method for simultaneously removing hydrogen sulfide and phosphine. It utilizes a microwave-impacted composite modified bed to activate modified straw biochar, and then uses the modified porous straw carbon in a dual-frequency ultrasonic bubble-breaking absorber to induce free radicals / active components, simultaneously oxidizing H2S and PH3 in industrial exhaust gas to H2SO4 and H3PO4. This invention proposes using readily available and inexpensive agricultural straw to prepare porous carbon, replacing traditional metal oxide activation for free radical removal of H2S and PH3 from industrial exhaust gas. This effectively overcomes the shortcomings of metal oxides, such as easy decomposition and deactivation in acidic solutions and metal ion leakage, while also possessing the advantages of widely available biochar raw materials and easy handling of deactivated catalysts. Furthermore, the microwave-impacted composite modified bed developed in this invention can achieve multi-stage activation and modification within a single reactor. Therefore, this device has outstanding comprehensive advantages, including simple and compact structure, short process flow, high mass transfer efficiency, high simultaneous pollutant removal efficiency, and a green and environmentally friendly process.

Description

Technical Field

[0001] This invention belongs to the field of air pollution control, specifically relating to a system and method for simultaneously removing hydrogen sulfide and phosphine based on photo-microwave synergistic modification of porous carbon activated free radicals. Background Technology

[0002] my country is a country that relies heavily on fossil fuels for energy, with fossil fuels accounting for over 70% of its total energy consumption and expected to maintain this dominant position for a long time to come. However, the industrial production of fossil fuels such as coal, natural gas, and oil all produce hydrogen sulfide (H2S), a harmful substance. Furthermore, various industries, including chemical and pharmaceutical production and waste disposal, generate pollutants such as hydrogen sulfide (H2S) and phosphine (PH3). Hydrogen sulfide is a highly irritating and toxic gas. Under aerobic and humid conditions, it not only causes equipment corrosion and catalyst poisoning but also seriously threatens human safety. Phosphine is a highly toxic gas; its toxicity primarily affects the respiratory and nervous systems, irritating the lungs and causing emphysema and enlarged heart. With rapid economic development and increased environmental awareness, the removal of hydrogen sulfide and phosphine from industrial waste gases has become an increasingly important issue. The government has also formulated corresponding laws and regulations to strictly limit the emission of hydrogen sulfide and phosphine. Researching and developing efficient removal technologies for hydrogen sulfide and phosphine has become a hot topic of interest for scientists worldwide.

[0003] Domestic and international researchers have conducted extensive research on the removal of hydrogen sulfide and phosphine from waste gases and developed numerous methods for their removal. Based on the dry / wet nature of the removal process, these methods can be broadly categorized into dry and wet methods. Dry methods utilize the reducing and combustible properties of hydrogen sulfide and phosphine, employing fixed oxidants or absorbents for desulfurization or direct combustion. These methods include fixed-bed adsorption, membrane separation, molecular sieve methods, pressure swing adsorption (PSA), and cryogenic separation. The desulfurization / phosphorus agents and catalysts used primarily include activated carbon and various metal oxides. While dry methods offer high efficiency for sulfur / phosphorus removal, they suffer from drawbacks such as high equipment investment, the need for intermittent regeneration of desulfurization / phosphorus agents, and low sulfur / phosphorus capacity. They are generally suitable for fine desulfurization / phosphorus removal of gases.

[0004] Wet removal technologies can be categorized into chemical absorption, physical absorption, physicochemical absorption, and wet oxidation based on their removal mechanisms. Chemical absorption utilizes the reversible reaction between hydrogen sulfide / phosphine and a chemical solvent to remove hydrogen sulfide / phosphine. Common methods include the amine method, the hot carbonate method, and the ammonia method. Physical absorption utilizes the difference in solubility of different components in a specific solvent to remove hydrogen sulfide / phosphine, then regenerates the absorbent by releasing hydrogen sulfide through pressure reduction flash evaporation or other methods. Common physical solvent methods include the low-temperature methanol method, the polyethylene glycol dimethyl ether method, and the N-methylpyrrolidone method. Physicochemical absorption mixes physical and chemical solvents, combining the properties of both; a typical example is the sulfoneamine method. Wet oxidation refers to using an oxidant to oxidize hydrogen sulfide / phosphine into elemental sulfur / phosphorus or sulfuric acid / phosphoric acid solutions for recovery. Based on different oxidation mechanisms, wet oxidation methods can be mainly divided into catalytic oxidation methods, represented by iron-based and vanadium-based methods, and direct oxidation methods, represented by hydrogen peroxide and potassium permanganate methods. Currently, wet removal processes for hydrogen sulfide / phosphine also have many problems. For example, newly synthesized organic absorbents or oxidants are expensive, have unstable performance, and are even toxic. Oxidants such as potassium permanganate produce complex byproducts during the reaction process, making product utilization difficult. Although oxidants such as hydrogen peroxide are clean and environmentally friendly, their oxidation efficiency is low, causing the removal process to fail to meet increasingly stringent environmental requirements. In summary, there is currently no stable, reliable, economical, and effective process suitable for the removal of low to medium concentrations of hydrogen sulfide / phosphine from waste gas. Therefore, while improving existing removal technologies, actively developing new economical and efficient hydrogen sulfide / phosphine removal technologies for waste gas has significant theoretical and practical implications.

[0005] Furthermore, hydrogen sulfide and phosphine often coexist in the exhaust gases of many industrial production plants. Many existing removal technologies are developed specifically for the individual removal of hydrogen sulfide and phosphine, which suffer from drawbacks such as high initial investment, complex processes, and high energy consumption and costs. In contrast, achieving simultaneous removal of hydrogen sulfide and phosphine in a single unit can effectively reduce the complexity of the equipment and processes, decrease investment and operating energy consumption / costs, and has promising development prospects and industrial application value. Currently, many technologies for the simultaneous removal of multiple gaseous pollutants have been developed both domestically and internationally.

[0006] Among various common simultaneous removal technologies, the free radical advanced oxidation simultaneous removal technology has comprehensive technical advantages such as strong oxidation capacity and green environmental protection, making it a promising flue gas simultaneous removal technology. However, the development of existing free radical advanced oxidation simultaneous removal technologies has been relatively slow. The main problems can be summarized as follows: (I) Using electrochemical activation removal technology, photochemical activation removal technology, and microwave activation removal technology alone has shortcomings such as low energy utilization efficiency and low activation efficiency (generally requiring the synergistic use of other catalysts or activators); (II) Ultrasonic and thermal activation removal technologies have problems such as low free radical activation efficiency and low pollutant removal efficiency, and are usually only used as auxiliary enhancement methods in combination with other technologies; (III) Transition metal ion activation removal technology has problems such as difficulty in separating and recovering transition metal ions and secondary pollution; (IV) Transition metal oxide activation removal technology has problems such as easy decomposition and deactivation of metal oxides in acidic solutions. The above four key problems are the main bottlenecks or obstacles hindering the large-scale industrial application of free radical advanced oxidation simultaneous desulfurization, denitrification, and mercury removal technology. Furthermore, extensive scientific research and industrial practice have confirmed that the main rate-controlling step in a gas-liquid-solid three-phase reaction process is mass transfer. Therefore, using traditional reactors for simultaneous desulfurization, denitrification, and mercury removal often results in large reactor volumes and high energy consumption, necessitating further research and development of highly efficient multiphase reactors capable of achieving good mixing and enhanced mass transfer. Summary of the Invention

[0007] To address the aforementioned technical challenges and bottlenecks, this invention provides a novel system and method for simultaneously removing hydrogen sulfide and phosphine, primarily based on a method for activating free radicals through photo-microwave synergistic modification of porous carbon. In this invention, modified straw biochar is first activated using a microwave-impacted composite modification bed. Then, the modified porous straw carbon is used in a dual-frequency ultrasonic bubble-breaking absorber to induce free radicals / active components, simultaneously oxidizing H2S and PH3 in industrial exhaust gas to H2SO4 and H3PO4. The resulting H2SO4 and H3PO4 can be used to prepare agricultural compound fertilizer by adding ammonia; the removal process is green and pollution-free.

[0008] The basic principle of this invention is as follows:

[0009] (1) Straw biochar modification process: First, in the first modification zone (A1), microwave-assisted phosphoric acid activation of straw biochar is used to prepare porous carbon with expanded pores and increased specific surface area, generating abundant phosphorus-containing functional groups on its surface. Then, in the second modification zone (A2), vacuum ultraviolet light is used in conjunction with microwave decomposition of aniline to generate nitrogen-containing active molecules that attack the porous carbon surface to generate nitrogen-containing functional groups. Finally, in the third modification zone (A3), short-wave ultraviolet light is used in conjunction with microwave decomposition of hydrogen peroxide to generate oxygen-containing active molecules that attack the porous carbon surface to generate oxygen-containing functional groups. The above multi-step modification process can be represented by the following equations (1)-(3):

[0010]

[0011] (2) The process of generating free radicals and active components by activating persulfate with modified porous carbon: Activating persulfate (S2O8) in a bubble-breaking absorber (15) using modified porous carbon via dual-frequency ultrasound. 2- This generates highly oxidizing free radicals / active components (e.g., SO4). - ·、·OH、HO2·、·O、O3 and O2 1 The specific process can be represented by the following chemical reaction equation (4):

[0012]

[0013] (3) Simultaneous removal of pollutants: utilizing highly oxidizing free radicals / active components (e.g., SO4) - ·、·OH、HO2·、·O、O3 and O2 1 Simultaneously, H2S and PH3 in industrial exhaust gas are oxidized to H2SO4 and H3PO4, respectively, thus achieving the simultaneous removal of multiple pollutants. The specific process can be represented by the following chemical reactions (5)-(6):

[0014]

[0015] The porous carbon that loses its activity after the reaction can be returned to the microwave impacted composite modified bed (3) and regenerated through the activation modification process as shown in equations (1)-(3), so that it can regain its new activation free radical properties, thereby realizing the recycling of the activator. The generated H2SO4 and H3PO4 can be recycled through the product post-processing system at the tail end to obtain agricultural fertilizers with high added value.

[0016] Based on the above principles, the present invention provides a novel system for simultaneously removing hydrogen sulfide and phosphine, as follows: The system includes a microwave impactor composite modification bed 3 for modifying straw biochar and a dual-frequency ultrasonic bubble-breaking absorber 15 for inducing free radicals to simultaneously oxidize and remove hydrogen sulfide and phosphine; the microwave impactor composite modification bed 3 has multiple microwave emitters 7 on its internal sidewalls; the first modification zone A1 is located below the microwave impactor composite modification bed 3, and has multiple lateral impact nozzles 6 inside, and multiple bottom lift nozzles 2 at the bottom; the second modification zone A2 is located above the first modification zone A1, and has multiple vacuum ultraviolet lamps 8 and an aniline atomizer 11 inside. The aniline atomizer 11 is connected to an aniline feed tower 13. The third modification zone A3 is located above the second modification zone A2, and has multiple short-wave ultraviolet lamps 9 and a hydrogen peroxide atomizer 10 inside. The hydrogen peroxide atomizer 10 is connected to a hydrogen peroxide feed tower 12. The bottom of the microwave impact composite modified bed 3 is connected to the biochar feeder 1, and the side is connected to the lateral impact nozzle circulation device. The lateral impact nozzle circulation device is equipped with a first fan 4 and a constant temperature humidifier and phosphorus adder 5. The bottom of the microwave impact composite modified bed 3 is equipped with a total inlet e and a total outlet f for the microwave impact composite modified bed biochar.

[0017] The dual-frequency ultrasonic impact bubble-breaking absorber 15 internally includes a swirling jet 16, an impact jet 17, a demister 18, a gas distribution plate 19, a low-frequency ultrasonic transmitter 20, and a high-frequency ultrasonic transmitter 21. The dual-frequency ultrasonic impact bubble-breaking absorber 15 has a gas outlet h at the top, a gas inlet u at the bottom, a solution outlet i and a solution inlet q on the lower side, and a biochar inlet g at the bottom left side. These are connected to the total biochar outlet f of the microwave impact composite modified bed biochar via a pipe, and a second fan 14 for conveying modified biochar is installed on this connecting pipe. The side of the dual-frequency ultrasonic impact bubble-breaking absorber 15 has a solution circulation system connecting the impact jet 17, the biochar separation device 25, and the fresh liquid addition device 26. The biochar separation device 25 is equipped with a waste liquid discharge port j, a biochar discharge port k, and a solution circulation outlet m. The fresh solution addition device 26 is equipped with a fresh solution addition circulation inlet n, a fresh solution addition replenishment inlet o, and a fresh solution addition outlet p. A first solution pump 22 is installed on the pipeline between the solution discharge port i of the dual-frequency ultrasonic bubble-breaking absorber and the biochar separation device 25. A second solution pump 23 is installed on the pipeline between the solution circulation outlet m of the biochar separation device and the circulation inlet n of the fresh solution addition device. A third solution pump 24 is installed between the solution outlet p of the fresh solution addition device and the solution inlet q of the dual-frequency ultrasonic bubble-breaking absorber.

[0018] Furthermore, the first modified zone A1 is located below the second modified zone A2, and the second modified zone A2 is located below the third modified zone A3. The height H1 of the first modified zone A1 is between 120cm and 300cm, the height H2 of the second modified zone A2 is between 40cm and 150cm, and the height H3 of the third modified zone A3 is between 50cm and 160cm. The UV lamps in the second modified zone A2 and the third modified zone A3 are arranged in a longitudinal and transversely equidistant pattern, and the optimized range of the longitudinal and transverse spacing M2 is between 5cm and 20cm.

[0019] Furthermore, the inner wall of the dual-frequency ultrasonic impact bubble-breaking absorber 15 is provided with multiple swirling jets 16 and multiple impact jets 17. The swirling jets 16 are arranged at an angle A degrees to the diameter line, with the optimal angle A being between 30 and 60 degrees. The impact jets 17 are arranged facing each other on the same diameter line passing through the origin, and the impact jets in the same layer are kept on the same horizontal plane. Both the swirling jets 16 and the impact jets 17 are arranged in multiple layers, with alternating staggered arrangements. The longitudinal spacing H4 between each layer of swirling jets 16 and impact jets 17 is maintained between 60 cm and 160 cm. The initial velocity of the impact jets 17 is between 40.0 m / s and 160 m / s to ensure sufficient impact breaking strength and media mixing efficiency. The initial velocity of the swirling jets 16 is between 20.0 m / s and 80 m / s to ensure sufficient swirling velocity and macroscopic mixing intensity.

[0020] Furthermore, the low-frequency ultrasonic transmitter 20 and the high-frequency ultrasonic transmitter 21 within the dual-frequency ultrasonic bubble-breaking absorber 15 are arranged alternately and vertically. The low-frequency ultrasonic transmitter 20, the high-frequency ultrasonic transmitter 21, the swirling jet 16, and the impact jet 17 are all arranged alternately, and the vertical distance between them is 1 / 2 H4, with H4 maintained between 60cm and 160cm.

[0021] Furthermore, the microwave radiation power density within the first modification zone A1 of the microwave impact composite modification bed 3 needs to be maintained at 400 W / m². 3 ~2500W / m 3 Between these points, the microwave radiation power density within the second modification region A2 needs to be maintained at 200 W / m². 3 ~600W / m 3 During this period, the microwave radiation power density within the third modification region A3 needs to be maintained at 240 W / m. 3 ~480W / m 3 Between. The vacuum ultraviolet radiation power density inside the second modification zone A2 needs to be maintained at 50 W / m. 3 ~200W / m 3Between these points, the ultraviolet radiation power density within the third modification region A3 needs to be maintained at 80 W / m². 3 ~280W / m 3 between.

[0022] Furthermore, the concentration of aniline sprayed by the aniline atomizer 11 within the microwave impact composite modification bed 3 needs to be maintained between 0.02 mol / L and 1.2 mol / L. The concentration of H2O2 sprayed by the hydrogen peroxide atomizer 10 needs to be maintained between 0.05 mol / L and 3.0 mol / L. The concentration of phosphoric acid added to the constant temperature humidification phosphorus adder 5 is between 0.1 mol / L and 2.5 mol / L.

[0023] Furthermore, the optimal frequency range for the low-frequency ultrasonic transmitter 20 within the dual-frequency ultrasonic absorber 15 is 10kHz to 60kHz, and the optimal frequency range for the high-frequency ultrasonic transmitter 21 is 70kHz to 160kHz. The power of the low-frequency ultrasonic transmitter 20 needs to be maintained at 40W / m. 3 ~180W / m 3 During this period, the power of the high-frequency ultrasonic transmitter 21 needs to be maintained at 80W / m. 3 ~240W / m 3 between.

[0024] Furthermore, the optimized concentration range of persulfate in the bubble-breaking absorber 15 using dual-frequency ultrasound is 0.06 mol / L to 1.8 mol / L, the optimized solution pH is 0.08 to 6.8, the optimized reaction temperature is 35℃ to 78℃, the optimized dosage of modified porous carbon is 100 mg / L to 500 mg / L, and the optimized particle size distribution of modified porous carbon is 0.003 μm to 0.5 μm.

[0025] Furthermore, the optimized initial concentration ranges for flue gas pollutants H2S and PH3 are 100–25000 ppm and 50–8000 ppm, respectively.

[0026] This invention also discloses a method for simultaneously removing hydrogen sulfide and phosphine from porous carbon activated free radicals based on photo-microwave synergistic modification. The operation flow of the biochar modification and pollutant removal system is as follows:

[0027] I. Air enters biochar feeder 1 through air inlet a, and biochar enters biochar feeder 1 through biochar inlet b. After thorough mixing in biochar feeder 1, the air and biochar enter the bottom of microwave impact composite modified bed 3 through the total biochar inlet e, and then are sprayed into the first modification zone A1 through the bottom lift nozzle 2. The microwave radiator 7 arranged in the first modification zone A1 begins to emit microwaves, and the fan 4 and the side impact nozzle 6 on the side impact nozzle circulation device are all activated, which can draw the suspended biochar in the first modification zone A1 to achieve synchronous impact, thereby achieving strong mixing. The constant temperature humidifier and phosphorus adder 5 set on the side impact nozzle circulation device adds water vapor and phosphoric acid of a certain concentration and temperature to the airflow to synergistically activate the biochar with microwave, thereby achieving rapid pore expansion and increasing the specific surface area of ​​the biochar. In the first modification zone A1, the biochar subjected to microwave-assisted impaction can not only achieve rapid pore expansion and increase specific surface area, but also achieve preliminary enhancement of oxygen- and phosphorus-containing functional groups.

[0028] Biochar, after microwave activation and vigorous impact pore expansion in the first modification zone A1, becomes porous carbon. This porous carbon then proceeds to the second modification zone A2 for surface chemical modification. An aniline atomizer 11 sprays a certain concentration of aniline atomized solution as the nitrogen source for modification. A microwave radiator begins emitting microwaves for synergistic modification, while a vacuum ultraviolet lamp 8, upon activation, radiates 185nm vacuum ultraviolet radiation, decomposing aniline and H2O / O2 in the gas flow to produce various nitrogen- and oxygen-containing active components, which in turn attack the porous carbon surface, generating nitrogen- and oxygen-containing active functional groups. After modification in the second modification zone A2, the biochar continues to the third modification zone A3 for further modification. A hydrogen peroxide atomizer 10 sprays a certain concentration of atomized hydrogen peroxide solution as the oxygen source for modification. A microwave radiator 7 begins emitting microwaves for synergistic modification, while a short-wave ultraviolet lamp 9, upon activation, radiates 254nm short-wave ultraviolet radiation, decomposing hydrogen peroxide to produce various oxygen-containing active components, which in turn attack the porous carbon surface, generating abundant oxygen-containing active functional groups.

[0029] II. The modified porous carbon in the microwave-impacted composite modified bed 3 is transported from the total biochar outlet f of the microwave-impacted composite modified bed to the dual-frequency ultrasonic bubble-breaking absorber 15 via fan 4 for free radical activation and pollutant removal reactions. The porous carbon enters the dual-frequency ultrasonic bubble-breaking absorber 15 through the biochar inlet g, and under the synergistic enhancement of dual-frequency ultrasound, it activates persulfate-induced free radical oxidation to remove pollutants. During free radical activation and pollutant removal, the impact ejector 17 activates the impact spray mode to achieve efficient gas-liquid-solid collision and enhance the mass transfer reaction process. At the same time, the swirling ejector 16 also activates the swirling spray mode to achieve efficient gas-liquid-solid mixing and disturbance, further enhancing the overall macroscopic mixing efficiency within the reactor and promoting multiphase reactions. In addition to enhancing the mass transfer rate of gas-liquid-solid heterogeneous reaction processes through cavitation, dual-frequency ultrasound can also achieve rapid removal of products from porous carbon surfaces / pores, thereby realizing a multi-faceted synergistic effect of free radical activation, multiphase mass transfer, and catalyst cleaning, achieving mutual promotion and comprehensive efficiency improvement across multiple stages.

[0030] III. Industrial exhaust gas from the industrial plant enters the dual-frequency ultrasonic bubble-breaking absorber 15 through the gas inlet q, and after being bubbled by the gas distribution plate 19, it enters the reaction zone and mixes with the persulfate solution. In the persulfate solution in the reaction zone, the modified porous carbon activates the persulfate-induced free radicals / active components (SO4). - ·、·OH、HO2·、·O、O3 and O2 1 The solution reacts with H2S and PH3 in the flue gas, oxidizing them to H2SO4 and H3PO4, respectively, thus achieving simultaneous removal of multiple pollutants. The clean exhaust gas, after being separated and having its solution removed by demister 18, undergoes further separation of the solution and porous carbon via dual-frequency ultrasonic bubble-breaking 25. The separated waste porous carbon can be recycled from the biochar discharge port k of the biochar separation device through the biochar inlet b of the biochar feeder into the microwave impact composite modification bed 3 for further modification and regeneration. The separated solution is discharged from the solution circulation outlet m of the biochar separation device by solution pump 23 into the fresh solution addition device 26. After replenishing with new persulfate solution, it is then recycled back into the dual-frequency ultrasonic bubble-breaking absorber 15 through the solution outlet p of the fresh solution addition device to participate in the oxidation removal reaction. The newly added persulfate solution is fed into the new solution addition device 26 through the replenishment inlet o. After multiple cycles, the saturated waste solution containing H2SO4 and H3PO4 is discharged through the biochar separation device 25 and then sent to the tail product post-processing system.

[0031] IV. The product post-processing system includes an ammonia neutralization acid unit and a flue gas waste heat evaporation crystallization unit for preparing compound fertilizer. In the ammonia neutralization acid unit, H2SO4 and H3PO4 can react with the addition of ammonia to produce ammonium sulfate and ammonium phosphate. In the flue gas waste heat evaporation crystallization unit, agricultural fertilizer is prepared after evaporation and crystallization using boiler flue gas waste heat. Therefore, the entire removal process not only avoids secondary pollution but also yields important resources such as mercury and agricultural fertilizers like ammonium sulfate and ammonium phosphate, demonstrating promising development and industrial application prospects.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] (1) Existing free radical advanced oxidation technologies for removing multiple pollutants from flue gas generally have various shortcomings. For example, high-energy free radical activation and removal technologies such as electrochemical, ultraviolet light, and microwave have shortcomings such as low energy utilization efficiency and low free radical activation efficiency. Thermal activation and ultrasonic activation and removal technologies have problems such as low free radical yield and low pollutant removal efficiency, and are usually only used as auxiliary means in combination with other activation technologies. Transition metal ion activation and removal technologies have problems such as difficulty in recovering metal ions and secondary pollution. Transition metal oxide activation and removal technologies have advantages such as simple process and low equipment requirements, and metal oxide catalysts can be recycled and reused. However, common transition metal oxide catalysts mainly include iron oxide, copper oxide, manganese oxide, cobalt oxide, and cerium oxide, as well as a variety of mixed metal oxides. However, these transition metal oxides are all basic oxides, which are easily corroded and decomposed in acidic solutions (the oxidation and removal products of this process are sulfuric acid and phosphoric acid), thus becoming poisoned and deactivated, resulting in high application costs. The invention proposes using porous carbon from straw to replace traditional transition metal oxides for activating free radicals to remove gaseous pollutants. This effectively overcomes the shortcomings of metal oxides, such as easy decomposition and deactivation in acidic solutions and leakage of metal ions. It also has the advantages of straw biochar raw materials being widely available and deactivated catalysts being easy to handle, thus possessing good technical and economic advantages.

[0034] (2) Existing activator modification technologies and processes typically involve complex modification procedures and equipment, resulting in excessively long process flows and complex equipment, leading to huge initial investment and operating costs. Therefore, developing energy-saving and low-carbon modification technologies and processes with low energy consumption, low cost, and short process flow is an important research topic and development direction in this field. The microwave impaction composite modification bed developed in this invention can achieve multi-stage continuous modification in a single reactor, with outstanding advantages such as simple modification equipment and short process flow, and has good industrial development prospects.

[0035] (3) The removal of H2S and PH3 from tail gas by persulfate-induced free radical oxidation using a solid catalyst is a three-phase gas-liquid-solid reaction process. In complex heterogeneous reaction processes, the oxidation rate of free radicals is often extremely fast, so the multiphase mass transfer process is usually the rate-controlling step of the entire removal process. How to simply and efficiently enhance the mass transfer process is the key issue for achieving efficient removal of gaseous pollutants. However, the mass transfer efficiency of commonly used bubbling bed reactors and spray tower reactors in this field is low and cannot meet the requirements of industrial applications. The dual-frequency ultrasonic bubble-breaking absorber developed in this invention has extremely high performance in enhancing mixing and mass transfer (for example, the synergistic effect of the swirling jet and the impact jet can greatly enhance the macroscopic mixing of the medium in the reactor, while the synergistic effect of the dual-frequency ultrasonic waves can enhance the microscopic mixing of the medium through cavitation. The combined effect of the above two can further improve the mass transfer efficiency of the multiphase reaction), which can greatly promote the heterogeneous removal process and thus achieve higher simultaneous removal efficiency of pollutants (the simultaneous removal efficiency of both H2S and PH3 pollutants can reach 100%).

[0036] In summary, the modified and desorption system developed in this invention has outstanding comprehensive advantages such as simple and compact structure, short process flow, high mass transfer efficiency, high efficiency of simultaneous removal of pollutants, and green and environmentally friendly process. It is a new type of industrial exhaust gas purification method and system with broad application prospects. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the structure of the modified porous carbon activated free radical technology for the simultaneous removal of H2S and PH3 in an embodiment of the present invention.

[0038] Figure 2 This is a schematic diagram showing the arrangement and dimensions of the microwave transmitter in an embodiment of the present invention.

[0039] Figure 3 This is a schematic diagram showing the arrangement and dimensions of the bottom lifting nozzles in an embodiment of the present invention.

[0040] Figure 4 This is a schematic diagram showing the arrangement and dimensions of the lateral impact nozzles in an embodiment of the present invention.

[0041] Figure 5 This is a schematic diagram of the arrangement and dimensions of the ultraviolet lamps in an embodiment of the present invention.

[0042] Figure 6 This is a schematic diagram showing the arrangement and dimensions of the anti-tank jets in an embodiment of the present invention.

[0043] Figure 7 This is a schematic diagram showing the arrangement and dimensions of the swirling jets in an embodiment of the present invention.

[0044] Figure 8This is a schematic diagram showing the arrangement and dimensions of the ultrasonic transmitter in an embodiment of the present invention.

[0045] Figure reference numerals: 1. Biochar feeder; 2. Bottom lift nozzle; 3. Microwave impact composite modified bed; 3-1 Side wall of microwave impact composite modified bed; 3-2 Bottom wall of microwave impact composite modified bed; 4. Fan; 5. Constant temperature humidifier and phosphorus supplementer; 6. Lateral impact nozzle; 7. Microwave emitter; 8. Vacuum UV lamp; 9. Short-wave UV lamp; 10. Hydrogen peroxide atomizer; 11. Aniline atomizer; 12. Hydrogen peroxide feed tower; 13. Aniline feed tower; 14. Fan; 15. Dual-frequency ultrasonic bubble-breaking absorber; 15-1 Wall of dual-frequency ultrasonic bubble-breaking absorber; 16. Cyclone jet; 17. Impact jet; 18. Demister; 19. Gas distribution plate; 20. Low-frequency ultrasonic emitter; 21. High-frequency ultrasonic emitter; 22-24. Solution pump; 25. Biochar separation device; 26. New. Liquid addition device: a. Air inlet of biochar feeder; b. Biochar inlet of biochar feeder; c. Left outlet of biochar circulation; d. Right outlet of biochar circulation; e. Total inlet of microwave impact composite modified bed biochar; f. Total outlet of microwave impact composite modified bed biochar; g. Biochar inlet of dual-frequency ultrasonic bubble-breaking absorber; h. Gas outlet of dual-frequency ultrasonic bubble-breaking absorber; u. Gas inlet of dual-frequency ultrasonic bubble-breaking absorber; i. Solution discharge port of dual-frequency ultrasonic bubble-breaking absorber; j. Waste liquid discharge port of biochar separation device; k. Biochar discharge port of biochar separation device; m. Solution circulation outlet of biochar separation device; n. Circulating liquid inlet of fresh liquid addition device; o. Replenishing liquid inlet of fresh liquid addition device; p. Solution outlet of fresh liquid addition device; q. Solution inlet of dual-frequency ultrasonic bubble-breaking absorber. Detailed Implementation

[0046] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0047] like Figure 1 As shown, the system based on light-microwave synergistic modification of porous carbon to activate free radicals and simultaneously remove hydrogen sulfide and phosphine includes a microwave impact composite modification bed 3 for straw biochar modification and a dual-frequency ultrasonic bubble-breaking absorber 15 for inducing free radicals to simultaneously oxidize and remove hydrogen sulfide and phosphine.

[0048] Multiple microwave emitters 7 are installed on the inner sidewalls of the microwave impact composite modification bed 3. The first modification zone A1 is located below the microwave impact composite modification bed 3 and contains multiple lateral impact nozzles 6, with multiple bottom lift nozzles 2 at the bottom. The second modification zone A2 is located above the first modification zone A1 and contains multiple vacuum ultraviolet lamps 8 and aniline atomizers 11. The aniline atomizers 11 are connected to the aniline feed tower 13. The third modification zone A3 is located above the second modification zone A2 and contains multiple short-wave ultraviolet lamps 9 and hydrogen peroxide atomizers 10. The hydrogen peroxide atomizers 10 are connected to the hydrogen peroxide feed tower 12. The bottom of the microwave impact composite modification bed 3 is connected to the biochar feeder 1, and the side is connected to the lateral impact nozzle circulation device. The lateral impact nozzle circulation device is equipped with a first fan 4 and a constant temperature humidifier and phosphorus supplementer 5. The bottom of the microwave impacted composite modified bed 3 is equipped with a total inlet e of microwave impacted composite modified bed biochar and a total outlet f of microwave impacted composite modified bed biochar.

[0049] The dual-frequency ultrasonic impact bubble-breaking absorber 15 internally includes a swirling jet 16, an impact jet 17, a demister 18, a gas distribution plate 19, a low-frequency ultrasonic transmitter 20, and a high-frequency ultrasonic transmitter 21. The dual-frequency ultrasonic impact bubble-breaking absorber 15 has a gas outlet h at the top, a gas inlet u at the bottom, a solution outlet i and a solution inlet q on the lower side, and a biochar inlet g at the bottom left side. These are connected to the total biochar outlet f of the microwave impact composite modified bed biochar via a pipe, and a fan 14 for conveying modified biochar is installed on this connecting pipe. The side of the dual-frequency ultrasonic impact bubble-breaking absorber 15 has a solution circulation system connecting the impact jet 17, the biochar separation device 25, and the fresh liquid addition device 26. The biochar separation device 25 is equipped with a waste liquid discharge port j, a biochar discharge port k, and a solution circulation outlet m. The fresh solution addition device 26 is equipped with a fresh solution addition circulation inlet n, a fresh solution addition replenishment inlet o, and a fresh solution addition outlet p. A first solution pump 22 is installed on the pipeline between the solution discharge port i of the dual-frequency ultrasonic bubble-breaking absorber and the biochar separation device 25. A second solution pump 23 is installed on the pipeline between the solution circulation outlet m of the biochar separation device and the circulation inlet n of the fresh solution addition device. A third solution pump 24 is installed between the solution outlet p of the fresh solution addition device and the solution inlet q of the dual-frequency ultrasonic bubble-breaking absorber.

[0050] like Figure 1As shown, the first modified region A1 is located below the second modified region A2, and the second modified region A2 is located below the third modified region A3. The height H1 of the first modified region A1 is between 120cm and 300cm, the height H2 of the second modified region A2 is between 40cm and 150cm, and the height H3 of the third modified region A3 is between 50cm and 160cm.

[0051] like Figure 2 As shown, the microwave transmitters 7 are arranged in a straight line, and the horizontal and vertical spacing M1 between the microwave transmitters 7 are equal and both are between 10cm and 50cm.

[0052] like Figure 5 As shown, the ultraviolet lamps in the second modification zone A2 and the third modification zone A3 are arranged in a row with equal spacing in the longitudinal and transverse directions, and the optimized range of the longitudinal and transverse spacing M2 is between 5cm and 20cm.

[0053] like Figure 3 As shown, the bottom lifting nozzles 2 are arranged in a longitudinal and transverse row with equal spacing N1, and N1 is located between 10cm and 30cm.

[0054] like Figure 4 As shown, the lateral impact nozzles 6 and lateral impact nozzles 6 are arranged in a straight line, with equal longitudinal and transverse spacing L1, and both are located between 10cm and 50cm.

[0055] The inner wall of the dual-frequency ultrasonic bubble-breaking absorber 15 is equipped with multiple swirling jets 16 and multiple opposing jets 17. For example... Figure 7 As shown, the swirling jet 16 is arranged at an angle of A degrees to the diameter line, and the optimal angle of A is between 30 degrees and 60 degrees.

[0056] like Figure 6 As shown, the opposing jets 17 are arranged opposite each other on the same diameter line passing through the origin, and the jets in the same layer are kept on the same horizontal plane. Both the swirling jets 16 and the opposing jets 17 are arranged in multiple layers, with alternating staggered arrangements. The longitudinal spacing H4 between each layer of swirling jets 16 and opposing jets 17 is maintained between 60cm and 160cm. The initial velocity of the opposing jets 17 is between 40.0m / s and 160m / s to ensure sufficient impact crushing strength and media mixing efficiency. The initial velocity of the swirling jets 16 is between 20.0m / s and 80m / s to ensure sufficient swirling velocity and macroscopic mixing intensity.

[0057] like Figure 8As shown, the low-frequency ultrasonic transmitter 20 and the high-frequency ultrasonic transmitter 21 in the dual-frequency ultrasonic bubble-breaking absorber 15 are arranged alternately and vertically, with an angle of 90 degrees between them. The low-frequency ultrasonic transmitter 20, the high-frequency ultrasonic transmitter 21, the vortex jet 16, and the impact jet 17 are all arranged alternately, with a vertical spacing of 1 / 2 H4 between them, and H4 is maintained between 60cm and 160cm.

[0058] The microwave radiation power density within the first modification zone A1 of the microwave impact composite modification bed 3 needs to be maintained at 400 W / m². 3 ~2500W / m 3 Between these points, the microwave radiation power density within the second modification region A2 needs to be maintained at 200 W / m². 3 ~600W / m 3 During this period, the microwave radiation power density within the third modification region A3 needs to be maintained at 240 W / m. 3 ~480W / m 3 Between. The vacuum ultraviolet radiation power density inside the second modification zone A2 needs to be maintained at 50 W / m. 3 ~200W / m 3 Between these points, the ultraviolet radiation power density within the third modification region A3 needs to be maintained at 80 W / m². 3 ~280W / m 3 between.

[0059] The concentration of aniline sprayed by the aniline atomizer 11 within the microwave impact composite modification bed 3 needs to be maintained between 0.02 mol / L and 1.2 mol / L. The concentration of H2O2 sprayed by the hydrogen peroxide atomizer 10 needs to be maintained between 0.05 mol / L and 3.0 mol / L. The concentration of phosphoric acid added to the constant temperature humidification phosphorus adder 5 is between 0.1 mol / L and 2.5 mol / L.

[0060] The optimal frequency range for the low-frequency ultrasonic transmitter 20 within the dual-frequency ultrasonic bubble absorber 15 is 10kHz to 60kHz, while the optimal frequency range for the high-frequency ultrasonic transmitter 21 is 70kHz to 160kHz. The power of the low-frequency ultrasonic transmitter 20 needs to be maintained at 40W / m. 3 ~180W / m 3 During this period, the power of the high-frequency ultrasonic transmitter 21 needs to be maintained at 80W / m. 3 ~240W / m 3 between.

[0061] The optimized concentration range of persulfate in the bubble-breaking absorber 15 using dual-frequency ultrasound is 0.06 mol / L to 1.8 mol / L, the optimized solution pH is 0.08 to 6.8, the optimized reaction temperature is 35℃ to 78℃, the optimized dosage of modified porous carbon is 100 mg / L to 500 mg / L, and the optimized particle size distribution of modified porous carbon is 0.003 μm to 0.5 μm.

[0062] The optimized initial concentration ranges for flue gas pollutants H2S and PH3 are 100–25000 ppm and 50–8000 ppm, respectively.

[0063] This invention also discloses a method for simultaneously removing hydrogen sulfide and phosphine from porous carbon activated free radicals based on photo-microwave synergistic modification. The operation flow of the biochar modification and pollutant removal system is as follows:

[0064] I. Air enters biochar feeder 1 through air inlet a, and biochar enters biochar feeder 1 through biochar inlet b. After thorough mixing in biochar feeder 1, the air and biochar enter the bottom of microwave impact composite modified bed 3 through the total biochar inlet e, and then are sprayed into the first modification zone A1 through the bottom lift nozzle 2. The microwave radiator 7 arranged in the first modification zone A1 begins to emit microwaves, and the fan 4 and the side impact nozzle 6 on the side impact nozzle circulation device are all activated, which can draw the suspended biochar in the first modification zone A1 to achieve synchronous impact, thereby achieving strong mixing. The constant temperature humidifier and phosphorus adder 5 set on the side impact nozzle circulation device adds water vapor and phosphoric acid of a certain concentration and temperature to the airflow to synergistically activate the biochar with microwave, thereby achieving rapid pore expansion and increasing the specific surface area of ​​the biochar. In the first modification zone A1, the biochar subjected to microwave-assisted impaction can not only achieve rapid pore expansion and increase specific surface area, but also achieve preliminary enhancement of oxygen- and phosphorus-containing functional groups.

[0065] Biochar, after microwave activation and vigorous impact pore expansion in the first modification zone A1, becomes porous carbon. This porous carbon then proceeds to the second modification zone A2 for surface chemical modification. An aniline atomizer 11 sprays a certain concentration of aniline atomized solution as the nitrogen source for modification. A microwave radiator begins emitting microwaves for synergistic modification, while a vacuum ultraviolet lamp 8, upon activation, radiates 185nm vacuum ultraviolet radiation, decomposing aniline and H2O / O2 in the gas flow to produce various nitrogen- and oxygen-containing active components, which in turn attack the porous carbon surface, generating nitrogen- and oxygen-containing active functional groups. After modification in the second modification zone A2, the biochar continues to the third modification zone A3 for further modification. A hydrogen peroxide atomizer 10 sprays a certain concentration of atomized hydrogen peroxide solution as the oxygen source for modification. A microwave radiator 7 begins emitting microwaves for synergistic modification, while a short-wave ultraviolet lamp 9, upon activation, radiates 254nm short-wave ultraviolet radiation, decomposing hydrogen peroxide to produce various oxygen-containing active components, which in turn attack the porous carbon surface, generating abundant oxygen-containing active functional groups.

[0066] II. The modified porous carbon in the microwave-impacted composite modified bed 3 is transported from the total biochar outlet f of the microwave-impacted composite modified bed to the dual-frequency ultrasonic bubble-breaking absorber 15 via fan 4 for free radical activation and pollutant removal reactions. The porous carbon enters the dual-frequency ultrasonic bubble-breaking absorber 15 through the biochar inlet g, and under the synergistic enhancement of dual-frequency ultrasound, it activates persulfate-induced free radical oxidation to remove pollutants. During free radical activation and pollutant removal, the impact ejector 17 activates the impact spray mode to achieve efficient gas-liquid-solid collision and enhance the mass transfer reaction process. At the same time, the swirling ejector 16 also activates the swirling spray mode to achieve efficient gas-liquid-solid mixing and disturbance, further enhancing the overall macroscopic mixing efficiency within the reactor and promoting multiphase reactions. In addition to enhancing the mass transfer rate of gas-liquid-solid heterogeneous reaction processes through cavitation, dual-frequency ultrasound can also achieve rapid removal of products from porous carbon surfaces / pores, thereby realizing a multi-faceted synergistic effect of free radical activation, multiphase mass transfer, and catalyst cleaning, achieving mutual promotion and comprehensive efficiency improvement across multiple stages.

[0067] III. Industrial exhaust gas from the industrial plant enters the dual-frequency ultrasonic bubble-breaking absorber 15 through the gas inlet q, and after being bubbled by the gas distribution plate 19, it enters the reaction zone and mixes with the persulfate solution. In the persulfate solution in the reaction zone, the modified porous carbon activates the persulfate-induced free radicals / active components (SO4). - ·、·OH、HO2·、·O、O3 and O2 1The solution reacts with H2S and PH3 in the flue gas, oxidizing them to H2SO4 and H3PO4, respectively, thus achieving simultaneous removal of multiple pollutants. The clean exhaust gas, after being separated and having its solution removed by demister 18, undergoes further separation of the solution and porous carbon via dual-frequency ultrasonic bubble-breaking 25. The separated waste porous carbon can be recycled from the biochar discharge port k of the biochar separation device through the biochar inlet b of the biochar feeder into the microwave impact composite modification bed 3 for further modification and regeneration. The separated solution is discharged from the solution circulation outlet m of the biochar separation device by solution pump 23 into the fresh solution addition device 26. After replenishing with new persulfate solution, it is then recycled back into the dual-frequency ultrasonic bubble-breaking absorber 15 through the solution outlet p of the fresh solution addition device to participate in the oxidation removal reaction. The newly added persulfate solution is fed into the new solution addition device 26 through the replenishment inlet o. After multiple cycles, the saturated waste solution containing H2SO4 and H3PO4 is discharged through the biochar separation device 25 and then sent to the tail product post-processing system.

[0068] IV. The product post-processing system includes an ammonia neutralization acid unit and a flue gas waste heat evaporation crystallization unit for preparing compound fertilizer. In the ammonia neutralization acid unit, H2SO4 and H3PO4 can react with the addition of ammonia to produce ammonium sulfate and ammonium phosphate. In the flue gas waste heat evaporation crystallization unit, agricultural fertilizer is prepared after evaporation and crystallization using boiler flue gas waste heat. Therefore, the entire removal process not only avoids secondary pollution but also yields important resources such as mercury and agricultural fertilizers like ammonium sulfate and ammonium phosphate, demonstrating promising development and industrial application prospects.

[0069] The following are specific examples of the device simultaneously removing two pollutants, H2S and PH3, under different conditions:

[0070] Example 1:

[0071] In the microwave impact composite modification bed, the lateral and longitudinal spacing M1 between microwave transmitters is 30 cm. The height H1 of the first modification zone A1 is 100 cm, the height H2 of the second modification zone A2 is 50 cm, and the height H2 of the third modification zone A3 is 60 cm. The initial velocity of the lateral impact nozzle is 80 m / s, and the initial velocity of the airflow from the bottom lift nozzle is 30 m / s. The initial velocity of the impact jet is 80 m / s, and the initial velocity of the swirling jet is 60 m / s. The spacing between ultraviolet lamps is 6 cm. The microwave radiation power density in the first modification zone A1 is 1000 W / m². 3 The microwave radiation power density in the second modified region A2 is 300 W / m². 3 The power of the vacuum ultraviolet lamp tube is 60W / m 3 The power of the shortwave ultraviolet lamp is 80W / m 3The concentrations of phosphoric acid solution, H₂O₂ solution, and aniline solution were all 0.1 mol / L. The concentration of persulfate solution was 0.2 mol / L. The pH of the reaction solution was 2.8, the reaction temperature was 75℃, and the dosage of modified porous carbon was 180 mg / L. The concentrations of H₂S and PH₃ in the industrial exhaust gas were 3000 ppm and 3000 ppm, respectively.

[0072] Preliminary results from numerical simulation and pilot tests show that the simultaneous removal efficiencies of H2S and PH3 in flue gas can reach 60.7% and 69.6%, respectively.

[0073] Example 2:

[0074] In the microwave impact composite modification bed, the lateral and longitudinal spacing M1 between microwave transmitters is 30 cm. The height H1 of the first modification zone A1 is 100 cm, the height H2 of the second modification zone A2 is 50 cm, and the height H2 of the third modification zone A3 is 60 cm. The initial velocity of the lateral impact nozzle is 80 m / s, and the initial velocity of the airflow from the bottom lift nozzle is 30 m / s. The initial velocity of the impact jet is 80 m / s, and the initial velocity of the swirling jet is 60 m / s. The spacing between ultraviolet lamps is 6 cm. The microwave radiation power density in the first modification zone A1 is 1000 W / m². 3 The microwave radiation power density in the second modified region A2 is 300 W / m². 3 The power of the vacuum ultraviolet lamp tube is 100W / m 3 The power of the shortwave ultraviolet lamp is 120W / m 3 The concentrations of phosphoric acid solution, H₂O₂ solution, and aniline solution were all 0.1 mol / L. The concentration of persulfate solution was 0.2 mol / L. The pH of the reaction solution was 2.8, the reaction temperature was 75℃, and the dosage of modified porous carbon was 200 mg / L. The concentrations of H₂S and PH₃ in the industrial exhaust gas were 3000 ppm and 3000 ppm, respectively.

[0075] Preliminary results from numerical simulation and pilot tests show that the simultaneous removal efficiencies of H2S and PH3 in flue gas can reach 74.3% and 81.1%, respectively.

[0076] Example 3:

[0077] In the microwave impact composite modification bed, the lateral and longitudinal spacing M1 between microwave transmitters is 30 cm. The height H1 of the first modification zone A1 is 100 cm, the height H2 of the second modification zone A2 is 50 cm, and the height H2 of the third modification zone A3 is 60 cm. The initial velocity of the lateral impact nozzle is 80 m / s, and the initial velocity of the airflow from the bottom lift nozzle is 30 m / s. The initial velocity of the impact jet is 80 m / s, and the initial velocity of the swirling jet is 60 m / s. The spacing between ultraviolet lamps is 6 cm. The microwave radiation power density in the first modification zone A1 is 1000 W / m². 3 The microwave radiation power density in the second modified region A2 is 300 W / m². 3 The power of the vacuum ultraviolet lamp tube is 100W / m 3 The power of the shortwave ultraviolet lamp is 120W / m 3 The concentrations of phosphoric acid solution, H₂O₂ solution, and aniline solution were all 0.2 mol / L. The concentration of persulfate solution was 0.2 mol / L. The pH of the reaction solution was 2.8, the reaction temperature was 75℃, and the dosage of modified porous carbon was 200 mg / L. The concentrations of H₂S and PH₃ in the industrial exhaust gas were 3000 ppm and 3000 ppm, respectively.

[0078] Preliminary results from numerical simulation and pilot tests show that the simultaneous removal efficiencies of H2S and PH3 in flue gas can reach 85.4% and 89.7%, respectively.

[0079] Example 4:

[0080] In the microwave impact composite modification bed, the lateral and longitudinal spacing M1 between the microwave transmitters is 30 cm. The height H1 of the first modification zone A1 is 100 cm, the height H2 of the second modification zone A2 is 50 cm, and the height H2 of the third modification zone A3 is 60 cm. The initial velocity of the lateral impact nozzle is 80 m / s, and the initial velocity of the airflow from the bottom lift nozzle is 30 m / s. The initial velocity of the impact jet is 80 m / s, and the initial velocity of the swirling jet is 60 m / s. The spacing between the ultraviolet lamps is 6 cm. The microwave radiation power density in the first modification zone A1 is 1000 W / m². 3 The microwave radiation power density in the second modified region A2 is 300 W / m². 3 The power of the vacuum ultraviolet lamp tube is 100W / m 3 The power of the shortwave ultraviolet lamp is 120W / m 3The concentrations of phosphoric acid solution, H₂O₂ solution, and aniline solution were 0.3 mol / L and 0.5 mol / L, respectively. The concentration of persulfate solution was 0.5 mol / L, the pH of the reaction solution was 2.8, the reaction temperature was 75℃, and the dosage of modified porous carbon was 200 mg / L. The concentrations of H₂S and PH₃ in the industrial exhaust gas were 3000 ppm and 3000 ppm, respectively.

[0081] Preliminary results from numerical simulation and pilot tests show that the simultaneous removal efficiencies of H2S and PH3 in flue gas can reach 92.1% and 98.4%, respectively.

[0082] Example 5:

[0083] In the microwave impact composite modification bed, the lateral and longitudinal spacing M1 between microwave transmitters is 30 cm. The height H1 of the first modification zone A1 is 100 cm, the height H2 of the second modification zone A2 is 50 cm, and the height H2 of the third modification zone A3 is 60 cm. The initial velocity of the lateral impact nozzle is 80 m / s, and the initial velocity of the airflow from the bottom lift nozzle is 30 m / s. The initial velocity of the impact jet is 80 m / s, and the initial velocity of the swirling jet is 60 m / s. The spacing between ultraviolet lamps is 6 cm. The microwave radiation power density in the first modification zone A1 is 1000 W / m². 3 The microwave radiation power density in the second modified region A2 is 300 W / m². 3 The power of the vacuum ultraviolet lamp tube is 150W / m 3 The power of the shortwave ultraviolet lamp is 160W / m 3 The concentrations of phosphoric acid solution, H₂O₂ solution, and aniline solution were 0.5 mol / L and 0.3 mol / L, respectively. The concentration of persulfate solution was 1.0 mol / L, the pH of the reaction solution was 2.8, the reaction temperature was 75℃, and the dosage of modified porous carbon was 260 mg / L. The concentrations of H₂S and PH₃ in the industrial exhaust gas were 3000 ppm and 3000 ppm, respectively.

[0084] Preliminary results from numerical simulation and pilot tests show that the simultaneous removal efficiencies of H2S and PH3 in flue gas can reach 100% and 100%, respectively.

[0085] The method described in this invention can remove H2S and PH3 simultaneously with efficiencies of 100% and 100% respectively, exhibiting extremely high efficiency in removing multiple pollutants at the same time. It can achieve the simultaneous removal of single or multiple flue gas pollutants without generating wastewater or waste liquid, thus well meeting the current stringent ultra-low emission requirements and possessing extremely significant technological competitive advantages.

[0086] The embodiments described above are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A system for simultaneously removing hydrogen sulfide and phosphine, characterized in that, The system includes a microwave impact composite modification bed (3) for biochar modification and a dual-frequency ultrasonic bubble-breaking absorber (15) for inducing free radicals to simultaneously oxidize and remove hydrogen sulfide and phosphine; the microwave impact composite modification bed (3) is provided with multiple microwave emitters (7) on its internal sidewalls; the interior of the microwave impact composite modification bed (3) is divided into a first modification zone (A1), a second modification zone (A2), and a third modification zone (A3) from bottom to top; the first modification zone (A1) is provided with multiple lateral impact nozzles (6), and the bottom of the first modification zone (A1) is provided with multiple bottom lift nozzles (2); the second modification zone (A2) is provided with multiple vacuum ultraviolet lamps (8) and an aniline atomizer (11); the aniline atomizer (11) is connected to an aniline feed tower (13); the third modification zone (A3) is provided with multiple short-wave ultraviolet lamps (9) and a hydrogen peroxide atomizer (10); the hydrogen peroxide atomizer (10) The microwave impact composite modified bed (3) is connected to the hydrogen peroxide feed tower (12); the bottom of the microwave impact composite modified bed biochar is provided with a total inlet (e) and a total outlet (f) of microwave impact composite modified bed biochar; the internal side wall of the dual-frequency ultrasonic bubble-breaking absorber (15) is alternately provided with a swirling jet (16) and a counter-jet jet (17); the dual-frequency ultrasonic bubble-breaking absorber (15) is also provided with a gas distribution plate (19), a low-frequency ultrasonic transmitter (20), a high-frequency ultrasonic transmitter (21) and a demister (18); the top of the dual-frequency ultrasonic bubble-breaking absorber (15) is provided with a dual-frequency ultrasonic bubble-breaking absorber gas outlet (h), the bottom is provided with a dual-frequency ultrasonic bubble-breaking absorber gas inlet (u), and the left bottom is provided with a dual-frequency ultrasonic bubble-breaking absorber biochar inlet (g), which is connected to the total outlet (f) of microwave impact composite modified bed biochar through a pipe; the dual-frequency ultrasonic bubble-breaking absorber (15) contains a persulfate solution.

2. The system for simultaneously removing hydrogen sulfide and phosphine according to claim 1, characterized in that, The bottom of the microwave impact composite modified bed (3) is connected to the biochar feeder (1) through the total biochar inlet (e) of the microwave impact composite modified bed; the side impact nozzle (6) of the microwave impact composite modified bed (3) is connected to the side impact nozzle circulation device; the side impact nozzle circulation device is equipped with a first fan (4) and a constant temperature humidifier and phosphorus feeder (5).

3. The system for simultaneously removing hydrogen sulfide and phosphine according to claim 1, characterized in that, The dual-frequency ultrasonic bubble-breaking absorber (15) is provided with a solution circulation system on its side connecting the impact jet (17), the biochar separation device (25), and the fresh liquid addition device (26); the biochar separation device (25) is provided with a waste liquid discharge port (j), a biochar discharge port (k), and a solution circulation outlet (m); the fresh liquid addition device (26) is provided with a circulating liquid inlet (n), a replenishing liquid inlet (o), and a solution outlet (p); the dual-frequency ultrasonic bubble-breaking absorber (15) is provided with a solution discharge port (i) below its side. The system includes a first solution pump (22) and a second solution pump (23) on the pipeline between the solution discharge port (i) of the dual-frequency ultrasonic bubble-breaking absorber and the biochar separation device (25). A third solution pump (24) is provided between the solution circulation outlet (m) of the biochar separation device and the circulation inlet (n) of the new liquid addition device. A second fan (14) is provided on the pipeline between the solution outlet (p) of the new liquid addition device and the solution inlet (q) of the dual-frequency ultrasonic bubble-breaking absorber.

4. The system for simultaneously removing hydrogen sulfide and phosphine according to claim 1, characterized in that, The height H1 of the first modified zone (A1) is between 120 cm and 300 cm, the height H2 of the second modified zone (A2) is between 40 cm and 150 cm, and the height H3 of the third modified zone (A3) is between 50 cm and 160 cm. The vacuum ultraviolet lamps (8) and the short-wave ultraviolet lamps (9) are arranged in a longitudinal and transverse equidistant arrangement, with the longitudinal and transverse spacing M2 ranging from 5 cm to 20 cm. The microwave transmitters (7) are arranged in a longitudinal arrangement, with the transverse and longitudinal spacing M1 between them being equal and both between 10 cm and 50 cm. The longitudinal and transverse spacing N1 between the bottom lift nozzles (2) are equal and both between 10 cm and 30 cm. The initial velocity of the airflow in the bottom lift nozzles is between 10 m / s and 40 m / s. The lateral impact nozzles (6) are all arranged in a longitudinal arrangement, with the longitudinal and transverse spacing L1 being equal and both between 10 cm and 30 cm. The initial velocity of the airflow in the lateral impact nozzle (6) is between 50 m / s and 120 m / s.

5. The system for simultaneously removing hydrogen sulfide and phosphine according to claim 1, characterized in that, The swirling jets (16) are arranged at an angle of A degrees to the diameter line, with the angle A ranging from 30 to 60 degrees. The opposing jets (17) are arranged opposite each other on the same diameter line passing through the origin, and the opposing jets in the same layer are kept on the same horizontal plane. Both the swirling jets (16) and the opposing jets (17) are arranged in multiple layers with staggered intervals. The longitudinal spacing H4 between each layer of the swirling jets (16) and the opposing jets (17) is maintained between 60 cm and 160 cm. The initial velocity of the opposing jets (17) is between 40 m / s and 160 m / s, and the initial velocity of the swirling jets (16) is between 20 m / s and 80 m / s. The low-frequency ultrasonic transmitter (20), high-frequency ultrasonic transmitter (21), swirling jet (16) and impact jet (17) are arranged in a multi-layered, staggered manner; the vertical distance between the low-frequency ultrasonic transmitter (20) and the high-frequency ultrasonic transmitter (21) is 1 / 2 H4.

6. The system for simultaneously removing hydrogen sulfide and phosphine according to claim 2, characterized in that, The microwave radiation power density inside the first modified region (A1) is maintained at 400 W / m. 3 ~2500 W / m 3 Between these points, the microwave radiation power density within the second modification region (A2) remains at 200 W / m². 3 ~600 W / m 3 Between these points, the microwave radiation power density within the third modification region (A3) remained at 240 W / m². 3 ~480 W / m 3 Between; the vacuum ultraviolet radiation power density inside the second modified region (A2) remains at 50 W / m. 3 ~200 W / m 3 During this period, the ultraviolet radiation power density within the third modified region (A3) remains at 80 W / m². 3 ~280 W / m 3 The concentration of aniline sprayed by the aniline atomizer (11) is maintained between 0.02 mol / L and 1.2 mol / L; the concentration of H2O2 sprayed by the hydrogen peroxide atomizer (10) is maintained between 0.05 mol / L and 3.0 mol / L; and the concentration of phosphoric acid added in the constant temperature humidifier and phosphorus feeder (5) is between 0.1 mol / L and 2.5 mol / L.

7. The system for simultaneously removing hydrogen sulfide and phosphine according to claim 1, characterized in that, The frequency range of the low-frequency ultrasonic transmitter (20) in the dual-frequency ultrasonic bubble absorber (15) is 10 kHz ~ 60 kHz, and the frequency range of the high-frequency ultrasonic transmitter (21) is 70 kHz ~ 160 kHz; the power of the low-frequency ultrasonic transmitter (20) is maintained at 40 W / m. 3 ~180 W / m 3 Between these times, the power of the high-frequency ultrasonic transmitter (21) remained at 80 W / m. 3 ~240 W / m 3 The concentration range of persulfate in the dual-frequency ultrasonic bubble-breaking absorber (15) is 0.06 mol / L ~ 1.8 mol / L, the solution pH is 0.08 ~ 6.8, the reaction temperature is 35℃ ~ 78℃, the modified porous carbon dosage is 100 mg / L ~ 500 mg / L, and the modified porous carbon particle size distribution is 0.003 μm ~ 0.5 μm; the initial concentration ranges of flue gas pollutants H2S and PH3 are 100 ~ 25000 ppm and 50 ~ 8000 ppm, respectively.

8. A method for simultaneously removing hydrogen sulfide and phosphine, characterized in that, The operation process of the biochar modification and pollutant removal system is as follows: I. Air enters the biochar feeder (1) through the air inlet (a) of the biochar feeder, and biochar enters the biochar feeder (1) through the biochar inlet (b) of the biochar feeder; after the air and biochar are fully mixed in the biochar feeder (1), they enter the bottom of the microwave impact composite modified bed (3) through the total biochar inlet (e) of the microwave impact composite modified bed, and then are sprayed into the first modification zone (A1) through the bottom lift nozzle (2); the microwave radiator (7) arranged in the first modification zone (A1) begins to emit microwaves, and the air on the side impact nozzle circulation device is circulated. After the machine (4) and the side impact nozzle (6) are all started, they can draw the suspended biochar in the first modified zone (A1) to achieve synchronous impact and thus achieve strong mixing; the constant temperature humidifier and phosphorus adder (5) set on the side impact nozzle circulation device will add water vapor and phosphoric acid to the airflow to synergistically activate the biochar with microwave, thereby achieving rapid pore expansion and increase of specific surface area of ​​biochar; in addition to achieving rapid pore expansion and increase of specific surface area, the biochar in the first modified zone (A1) after microwave synergistic impact can also achieve the initial enhancement of oxygen-containing and phosphorus-containing functional groups; After being microwave-activated and subjected to intense impact pore-expanding in the first modification zone (A1), the biochar becomes porous carbon. This porous carbon then proceeds to the second modification zone (A2) for surface chemical modification. An aniline atomizer (11) sprays a certain concentration of aniline atomized solution as the nitrogen source for modification. A microwave radiator (7) begins to emit microwave-assisted modification, while a vacuum ultraviolet lamp (8) radiates 185 nm of vacuum ultraviolet radiation to decompose aniline and H2O / O2 in the gas stream, producing various nitrogen- and oxygen-containing active components. These components attack the porous carbon surface, generating nitrogen- and oxygen-containing active functional groups. After being modified in the second modification zone (A2), the biochar continues to the third modification zone (A3) for further modification. A hydrogen peroxide atomizer (10) sprays a certain concentration of atomized hydrogen peroxide solution as the oxygen source for modification. A microwave radiator (7) begins to emit microwave-assisted modification, while a shortwave ultraviolet lamp (9) radiates 254 nm of vacuum ultraviolet radiation. Short-wave ultraviolet radiation of nm decomposes hydrogen peroxide to produce a variety of oxygen-containing active components and attacks the porous carbon surface to produce abundant oxygen-containing active functional groups. II. The porous carbon modified in the microwave impacted composite modified bed (3) is transported from the total outlet (f) of the microwave impacted composite modified bed biochar to the dual-frequency ultrasonic bubble-breaking absorber (15) via a fan (4) to carry out free radical activation and pollutant removal reactions; the porous carbon enters the dual-frequency ultrasonic bubble-breaking absorber (15) through the biochar inlet (g) of the dual-frequency ultrasonic bubble-breaking absorber, and under the synergistic enhancement of dual-frequency ultrasound, it activates persulfate-induced free radical oxidation to remove pollutants; during the free radical activation and pollutant removal, the impact jet (17) starts the impact jet mode to achieve gas... The liquid-solid collision and enhanced mass transfer reaction process; at the same time, the swirling jet (16) also starts the swirling jet mode, which can realize the efficient mixing and disturbance of gas-liquid-solid, further enhance the overall macroscopic mixing efficiency in the reactor, and promote the multiphase reaction; the dual-frequency ultrasonic synergistic effect can not only enhance the mass transfer rate of the gas-liquid-solid heterogeneous reaction process through cavitation, but also realize the rapid removal of products on the porous carbon surface / pore interior, thereby realizing the multi-dimensional synergistic effect of free radical activation, multiphase mass transfer and catalyst cleaning, and realizing the mutual promotion and comprehensive efficiency improvement of multiple links; III. Industrial exhaust gas from the industrial plant enters the dual-frequency ultrasonic bubble-breaking absorber (15) through the gas inlet (q) and is bubbled through the gas distribution plate (19) before entering the reaction zone to mix with the persulfate solution; in the persulfate solution in the reaction zone, the modified porous carbon activates the persulfate-induced free radicals / active component SO4. - • OH, HO2•, • O, O3 and O2 1 It reacts with H2S and PH3 in the flue gas to oxidize H2S and PH3 to H2SO4 and H3PO4 respectively, achieving simultaneous removal of multiple pollutants; the clean exhaust gas after removal is separated and removed by the demister (18) and then discharged into the atmosphere from the gas outlet (h) of the dual-frequency ultrasonic bubble-breaking absorber; the reaction waste solution containing porous carbon can be discharged into the biochar separation device (25) by the solution pump (22) to separate the solution and porous carbon; the separated waste porous carbon can be sent back into the microwave impact composite modified bed (3) through the biochar discharge port (k) of the biochar separation device and the biochar inlet (b) of the biochar feeder. The modified and recycled solution is carried out again in the biochar separation device; the separated solution is discharged into the new solution addition device (26) by the solution pump (23) through the solution circulation outlet (m) of the biochar separation device, and then after the new persulfate solution is added, it is sent back into the dual-frequency ultrasonic bubble-breaking absorber (15) through the solution outlet (p) of the new solution addition device to participate in the oxidation and removal reaction; the newly added persulfate solution is sent into the new solution addition device (26) through the replenishment inlet (o) of the new solution addition device; after multiple cycles, the saturated waste solution containing H2SO4 and H3PO4 is discharged through the biochar separation device (25) and sent to the tail product post-processing system; IV. The product post-processing system includes an ammonia neutralization acid device and a flue gas waste heat evaporation crystallization device for preparing compound fertilizer; in the ammonia neutralization acid device, H2SO4 and H3PO4 can be reacted by adding ammonia to produce ammonium sulfate and ammonium phosphate, while in the flue gas waste heat evaporation crystallization device, agricultural fertilizer is prepared after evaporation and crystallization by boiler flue gas waste heat.

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