A system and method for flue gas purification using activated radicals of seaweed porous carbon

Abstract

The application provides a seaweed porous carbon activated radical flue gas purification system and method; in the application, firstly, a multiple radiation coupling modification reactor is used to activate and modify seaweed biochar, and then the modified seaweed biochar is used to induce radicals / active components in a sound-heat coupling pump-jet reactor to simultaneously oxidize SO2, NO x and Hg 0 in flue gas into H2SO4, HNO3 and Hg 2+ , and the generated H2SO4, HNO3 and Hg 2+ can be comprehensively utilized through multistage separation. The application proposes that the widely-sourced seaweed is used to prepare modified seaweed biochar to replace traditional metal oxide to activate radicals to remove various pollutants in flue gas, and the application has the advantages of widely-sourced biochar raw materials and easy treatment of deactivated catalysts. The multiple radiation coupling modification reactor developed by the application can realize multistage activation modification in one reactor, and the sound-heat coupling pump-jet reactor has extremely high intensified mixing and mass transfer performance, and is a novel flue gas purification method and system with broad application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of atmospheric pollution control, and particularly relates to a method and system for simultaneously removing sulfur, nitrogen oxides and mercury based on activated radicals of seaweed porous carbon prepared by multiple high-energy radiation. BACKGROUND

[0002] China is a country mainly using coal as energy, and coal accounts for more than 50% of the total energy consumption in China, and will still dominate in a long time in the future. However, various atmospheric pollutants such as sulfur dioxide, nitrogen oxides and heavy metal mercury are usually generated and discharged into the atmosphere during the coal combustion process. The discharge of these pollutants into the atmosphere will cause acid rain, photochemical smog and carcinogenic and teratogenic serious hazards. Therefore, it is of important theoretical significance and engineering practical value to research and develop environmentally friendly, economical and efficient flue gas desulfurization, denitrification and mercury removal technology and process, and it also has important social significance for the sustainable development of national economy.

[0003] Domestic and foreign scientists and engineers have developed various flue gas desulfurization, denitrification and mercury removal technologies and processes, but due to the limitations and timeliness of technology development, the existing flue gas desulfurization, denitrification and mercury removal technologies and processes only target at removing one kind of pollutant (for example, only one kind of sulfur dioxide, nitrogen oxides and heavy metal mercury can be removed) at the beginning of research and development, and it is difficult to achieve simultaneous removal of multiple pollutants. For example, the mainstream flue gas desulfurization and denitrification technologies currently used in domestic and foreign power plants and boilers are calcium-based flue gas wet desulfurization process and ammonia selective catalytic reduction denitrification method (i.e. SCR denitrification process). Although these two methods can achieve staged desulfurization and denitrification, they cannot achieve simultaneous removal of two pollutants in one reactor, and cannot achieve removal of heavy metal mercury in coal-fired flue gas. Therefore, if further removal of mercury in coal-fired flue gas is to be achieved, coal-fired flue gas mercury removal technology and device need to be further installed on this basis. However, the combined use of three processes will not only achieve simultaneous desulfurization, denitrification and mercury removal of flue gas, but also result in a large and complex removal system, a huge land occupation area, and high initial investment and operating costs of the system. There are more than 500,000 small and medium-sized coal-fired boilers, industrial kilns and waste incinerators in China's industrial and civil industries. If the enterprises using these small and medium-sized combustion facilities simultaneously install SO2, NO x and mercury removal devices and processes, they will face extremely huge economic pressure and very large energy consumption, which is not conducive to the large-scale promotion and implementation of related removal technologies and policies.

[0004] In summary, if SO2, NO xSimultaneous removal of SO2, NO and Hg, i.e. simultaneous desulfurization, denitrification and demercuration, is expected to greatly reduce the complexity and operating cost of the system, and has good market application prospects. The current developed flue gas simultaneous desulfurization, denitrification and demercuration technologies mainly include catalysis, adsorption, plasma removal, complex absorption, traditional oxidation and free radical advanced oxidation, etc. The plasma method has the defects of poor reliability and high operating energy consumption. The adsorption method has the defects of low removal efficiency (especially the removal efficiency of the key component NO is very low) and the reactor needs to be operated intermittently. The complex method (using complex iron and cobalt ammonia solution absorption) has the disadvantages of large regeneration loss of complexing agent and high regeneration energy consumption. The traditional oxidation method has the problems of high price of reagent (such as sodium chlorite and potassium permanganate, etc.), low oxidation capacity (such as hydrogen peroxide and persulfate, etc.), large consumption of oxidizing agent (easy to self-decompose), secondary pollution (such as the products of potassium permanganate and chlorite are difficult to handle), etc. The current widely concerned free radical advanced oxidation technology has made great progress, but there are still technical and economic problems such as large investment and high operating cost, and poor technical maturity, so these technologies still have a long way to go to industrial application, and more research and efforts are needed by the technical personnel in this field.

[0005] Among various common simultaneous removal technologies, the free radical advanced oxidation simultaneous removal technology has the comprehensive technical advantages of strong oxidation capacity and green and environmentally friendly process, and is a flue gas simultaneous removal technology process with good development prospects, but the development of the existing free radical advanced oxidation simultaneous removal technology is relatively slow, and the main problems can be summarized as follows: (I) the use of separate electrochemical activation removal technology, photochemical activation removal technology and microwave activation removal technology has the disadvantages of low energy utilization efficiency and low activation efficiency (generally needs to be coordinated with other catalysts or activators); (II) the thermal activation removal technology has the problems of low free radical activation efficiency and low pollutant removal efficiency; (III) the transition metal ion activation removal technology has the problems of difficult separation and recovery of transition metal ions and secondary pollution; (IV) the transition metal oxide activation removal technology has the problem of easy decomposition and deactivation of metal oxides in acidic solution. The above four key problems are the main bottlenecks or obstacles that hinder the large-scale industrial application of the free radical advanced oxidation simultaneous desulfurization, denitrification and demercuration technology. In addition, a large number of scientific researches and industrial practices have proved that the main rate control step of the gas-liquid-solid three-phase reaction process is the mass transfer process. Therefore, the use of traditional reactors for simultaneous desulfurization, denitrification and demercuration is prone to the disadvantages of large reactor volume and high operating energy consumption, and further research and development of high-efficiency multiphase reactors capable of implementing good mixing and mass transfer intensification are needed. SUMMARY

[0006] To address the aforementioned technical challenges and bottlenecks, this invention provides a method and system for preparing porous carbon from seaweed using multiple high-energy radiation methods to activate free radicals and simultaneously desulfurize, denitrify, and remove mercury. In this invention, firstly, a multi-radiation coupled modified reactor is used to activate modified seaweed biochar. Then, the modified seaweed biochar is used in an acoustic-thermal coupled pump-jet reactor to induce free radicals / active components to remove SO2 and NO from flue gas. x and Hg 0 Simultaneously oxidized to H2SO4, HNO3, and Hg. 2+ The oxidation produces H2SO4, HNO3, and Hg. 2+ Comprehensive resource utilization can be achieved through multi-stage separation, and the removal process produces no secondary pollution.

[0007] The basic principles of the method and system described in this invention are as follows:

[0008] (1) Modification process of seaweed biochar: First, seaweed biochar was prepared by microwave-assisted H2O2 activation to expand the pores, while generating abundant oxygen-containing functional groups on its surface. Then, urea and oxygen were activated by ultraviolet light-assisted corona discharge to generate oxygen- and nitrogen-containing active components. The generated oxygen- and nitrogen-containing active components formed abundant oxygen- and nitrogen-containing functional groups on the surface of the seaweed porous carbon. The above multi-step modification process can be represented by the following equations (1)-(4):

[0009]

[0010] (2) The process of generating free radicals and active components by activating potassium persulfate composite salt with modified seaweed porous carbon: Potassium persulfate composite salt (HSO5) is activated by modified seaweed porous carbon in an acoustic-optical coupled pump-jet reactor (13). - This generates highly oxidizing free radicals / active components (e.g., SO4). - ·、·OH、·O and O2 1 The specific process can be represented by the following chemical reaction equation (5):

[0011]

[0012] (3) Pollutant removal process: Utilizing free radicals / active components with extremely strong oxidizing properties (e.g., SO42-) - ·、·OH and O2 1 Oxidize SO2 and NO in flue gas x and Hg 0 It can dispose of SO2 and NO x and Hg 0 They are oxidized to H2SO4, HNO3 and Hg respectively. 2+ This achieves the simultaneous removal of multiple pollutants. The specific process can be represented by the following chemical reactions (6)-(8):

[0013] SO4 - ·+·OH+·O+O2 1 +SO2+H2O→H2SO4 (6)

[0014] SO4 - ·+·OH+O2 1 +·O+NO x +H2O→HNO3 (7)

[0015] SO4 - ·+·OH+·O+O2 1 +Hg 0 +H2O→Hg 2+

[0016] The inactivated seaweed porous carbon after the reaction can be returned to the multiple radiation coupling modification reactor (3) to realize new modification and regeneration through the activation modification process as in equations (1)-(4), so that the activated free radicals are regenerated, thereby realizing the recycling of the activated agent. The generated H2SO4, HNO3 and Hg 2+ The comprehensive resource utilization of the reaction products can be realized through the multi-stage comprehensive resource utilization system at the tail, and the whole removal process is free of secondary pollution.

[0017] Based on the above principle, the application discloses a flue gas purification system for preparing seaweed porous carbon activated free radicals based on multiple high-energy radiations. The flue gas purification system of the application mainly refers to simultaneous flue gas desulfurization, denitrification and mercury removal. The system comprises a multiple radiation coupling modification reactor 3 for seaweed biochar modification and an acousto-optic coupling pump jet reactor 13 for inducing free radical desulfurization, denitrification and mercury removal.

[0018] A plurality of microwave emitters 4 are arranged on the inner side wall surface of the multiple radiation coupling modification reactor 3. A first modification zone A1 is located below the multiple radiation coupling modification reactor 3 and is internally provided with a plurality of H2O2 atomizing nozzles 7, which are connected with an H2O2 storage tower 5. A second modification zone A2 is located above the multiple radiation coupling modification reactor 3 and is internally provided with a corona discharge emitter 9 and a vacuum ultraviolet lamp tube 10. A urea atomizing nozzle 8 is arranged below the modification zone A2 and is connected with a urea storage tower 6. A gas-solid nozzle 2 for spraying seaweed biochar is arranged at the bottom of the multiple radiation coupling modification reactor 3. The bottom of the multiple radiation coupling modification reactor 3 is connected with an impingement mixer 1, and the top is connected with a reheating device 11. The multiple radiation coupling modification reactor 3 is provided with a multiple radiation coupling modification reactor biochar inlet d and a multiple radiation coupling modification reactor biochar outlet e.

[0019] The inside of the acousto-optic coupling pump-jet reactor 13 is provided with a high-speed jet device 14, a vacuum ultraviolet lamp 15, an ultrasonic transmitter 16, a gas distribution device 17 and a demister 18. The top of the acousto-optic coupling pump-jet reactor 13 is provided with an acousto-optic coupling pump-jet reactor flue gas outlet h, the bottom is provided with an acousto-optic coupling pump-jet reactor flue gas inlet q, the lower side is provided with an acousto-optic coupling pump-jet reactor solution discharge port i and an acousto-optic coupling pump-jet reactor solution inlet p, the bottom left side is provided with an acousto-optic coupling pump-jet reactor biochar inlet g, and is connected with the reheating device outlet f of the reheating device 11 through a pipeline, and a modified biochar conveying fan 12 is arranged on the connecting pipeline. The side of the acousto-optic coupling pump-jet reactor 13 is provided with a circulating system constructed by a liquid-solid rapid separation device 19 and a solution supplementing device 20, which are connected with the acousto-optic coupling pump-jet reactor solution discharge port i and the acousto-optic coupling pump-jet reactor solution inlet p through pipelines, and a solution pump one 21, a solution pump two 22 and a solution pump three 23 for conveying solution are arranged on the pipelines.

[0020] A plurality of microwave radiators 4 are arranged on the wall surfaces on the left and right sides of the first modification zone A1 below the multiple radiation coupling modification reactor 3, and the microwave radiators are arranged in a row. The transverse and longitudinal spacings M1 between each microwave radiator 4 are between 15cm and 60cm, and the transverse and longitudinal spacings are the same. The longitudinal and transverse spacings N1 between the gas-solid nozzles at the bottom of the multiple radiation coupling modification reactor 3 are equal, and are between 10cm and 40cm.

[0021] The multiple radiation coupling modification reactor 3 is provided with a first modification zone A1 and a second modification zone A2, and the first modification zone A1 is below the second modification zone A2. The height H1 of the first modification zone A1 is between 100cm and 400cm, and the height H1 of the second modification zone A2 is between 60cm and 200cm.

[0022] The inside wall of the acousto-optic coupling pump-jet reactor 13 is provided with a plurality of high-speed jet devices 14. The high-speed jet devices 14 are arranged at an angle of 45 degrees on the same circumference, and the high-speed jet devices arranged opposite each other are on the same axis (i.e. on the diameter line passing through the origin). The high-speed jet devices 14 are arranged in multiple layers from top to bottom, and the longitudinal spacing H3 between each layer is kept between 60cm and 100cm. The initial speed of the high-speed jet devices 14 is between 20.0m / s and 120m / s, so as to ensure sufficient impact crushing strength and medium mixing efficiency.

[0023] Further, the ultraviolet lamp tubes and ultrasonic transmitters in the photoacoustic coupling pump jet reactor 13 are arranged in sequence and at intervals, and the two adjacent sides of the ultrasonic transmitter are arranged with a 185 nm vacuum ultraviolet lamp tube and a 254 nm short wave ultraviolet lamp tube in sequence (i.e., the ultraviolet lamp tube and the ultrasonic transmitter are arranged in sequence as ultrasonic transmitter-185 nm vacuum ultraviolet lamp tube-254 nm short wave ultraviolet lamp tube). The ultraviolet lamp tubes and ultrasonic transmitters are arranged on the same concentric circle with the same radial spacing J1, and the optimal range of J1 is 5 cm to 40 cm. The arc line spacing (C1, D1, E1) of the ultraviolet lamp tubes or ultrasonic transmitters on each arc is kept the same.

[0024] Further, the microwave radiation power density inside the first modification zone A1 needs to be kept between 500 W / m 3 and 4000 W / m 3 , the corona discharge emitter power inside the second modification zone A2 needs to be kept between 100 W / m 3 and 800 W / m 3 , and the vacuum ultraviolet light lamp power needs to be kept between 40 W / m 3 and 200 W / m 3 .

[0025] Further, the molar concentration of H2O2 sprayed by the H2O2 atomizing nozzle 7 in the multiple radiation coupling modification reactor 3 needs to be kept between 0.5 mol / L and 2.5 mol / L, and the molar concentration of the urea solution sprayed by the urea atomizing nozzle 8 needs to be kept between 0.01 mol / L and 2.0 mol / L.

[0026] Further, the optimal concentration range of peroxymonosulfate for realizing simultaneous desulfurization, denitrification and demercuration in the photoacoustic coupling pump jet reactor 13 is 0.02 mol / L to 2.5 mol / L, the optimal solution pH is 0.05 to 6.5, the optimal reaction temperature is 30°C to 80°C, and the optimal modification seaweed biochar dosage is 50 mg / L to 600 mg / L.

[0027] Further, the ultraviolet light lamp tubes in the photoacoustic coupling pump jet reactor 13 adopt the cross arrangement of vacuum ultraviolet light (center wavelength 185 nm) and short wave ultraviolet light (center wavelength 254 nm), and the ultraviolet light lamp power in the photoacoustic coupling pump jet reactor 13 needs to be kept between 50 W / m 3 and 180 W / m 3 . The ultrasonic transmitter power in the photoacoustic coupling pump jet reactor 13 needs to be kept between 100 W / m 3 and 400 W / m 3 .

[0028] Further, the flue gas pollutants SO2, NO x , and Hg0 The optimized initial concentration ranges of the modified seaweed biochar are 100-6000 ppm, 100-1800 ppm and 40 μg / m 3 <800 μg / m 3 The optimized particle size of the modified seaweed biochar is 0.002 μm-0.8 μm.

[0029] A method for preparing seaweed porous carbon activated free radicals for flue gas purification: the operation process of the biochar modification and pollutant removal system is as follows:

[0030] I. Air enters the impingement mixer 1 from the air inlet a of the impingement mixer, half of the seaweed biochar enters the impingement mixer 1 from the biochar left inlet b of the impingement mixer, and the other half of the seaweed biochar enters the impingement mixer 1 from the biochar left inlet c of the impingement mixer. The opposite impingement of the two biochar streams can produce intense mixing and suspension, and then enter the multi-radiation coupling modification reactor 3 through the biochar inlet d of the multi-radiation coupling modification reactor under the air carrying. The H2O2 atomizing nozzle 7 starts to spray the atomized H2O2 solution into the first modification zone A1. The microwave radiator 4 arranged in the first modification zone A1 starts to emit microwaves, and cooperates with H2O2 to induce free radical activated modification of seaweed biochar. Through the cooperation of microwaves and H2O2, the seaweed biochar can be rapidly expanded and the specific surface area can be improved, and the generated free radicals can also produce abundant oxygen-containing functional groups on the surface of the seaweed biochar. The seaweed porous carbon preliminarily modified in the first modification zone A1 continues to enter the second modification zone A2. The urea atomizing nozzle 8 sprays atomized urea solution with a certain concentration as a modified nitrogen source, and the corona discharge emitter 9 and the vacuum ultraviolet lamp tube 10 cooperate to induce oxygen-containing and nitrogen-containing active components to modify the surface of the seaweed porous carbon, and further form oxygen-containing and nitrogen-containing active functional groups on the surface of the biochar.

[0031] II. The modified seaweed biochar from the multiple radiation coupling modification reactor 3 enters the reheating device 11 through the modified seaweed biochar outlet e to avoid the condensation and agglomeration of the biochar, and then is transported by the transport fan 12 to the sound-light coupling pump-jet reactor 13 to perform the free radical activation and pollutant removal reaction. The modified seaweed porous carbon enters the sound-light coupling pump-jet reactor 13 through the sound-light coupling pump-jet reactor biochar inlet g, and is activated by the ultraviolet light emitted by the vacuum ultraviolet lamp tube 15, the ultrasonic wave emitted by the ultrasonic wave emitter 16, and the potassium peroxymonosulfate composite salt induced free radical oxidation to remove pollutants. During the free radical activation and pollutant removal reaction, the high-speed jet device 14 starts the jet mode, so that efficient mixing of gas, liquid and solid can be achieved. The ultraviolet light can induce more high-activity free radicals in cooperation with the seaweed porous carbon, and the ultrasonic wave can strengthen the mass transfer rate of the heterogeneous reaction through cavitation, and also can remove the products on the surface and inside the pores of the seaweed porous carbon, so that the multiple synergies of free radical activation, multiphase mass transfer and catalyst cleaning are achieved, and mutual promotion is achieved.

[0032] III. The flue gas from the boiler enters the sound-light coupling pump-jet reactor 13 through the sound-light coupling pump-jet reactor flue gas inlet q, and enters the reaction zone after bubbling through the gas distribution device 17 to mix with the potassium peroxymonosulfate composite salt solution. In the potassium peroxymonosulfate composite salt solution in the reaction zone, the modified seaweed porous carbon activates the free radicals / active components (such as SO4 - , ·OH and O2 1 ) induced by the potassium peroxymonosulfate composite salt to have oxidation removal reactions with SO2, NO x and Hg 0 in the flue gas, and SO2, NO x and Hg 0 are oxidized to H2SO4, HNO3 and Hg 2+, HNO3 and Hg2+ in the saturated waste solution are removed by the liquid-solid rapid separation device 19, and the waste solution is discharged from the liquid-solid rapid separation device waste solution discharge port j and sent to the tail-end multi-stage comprehensive resource utilization system. 2+

[0033] IV. The multi-stage comprehensive resource utilization system comprises a mercury separation device, an ammonia neutralization acid device and a flue gas waste heat evaporation crystallization fertilizer preparation device. 2+ In the mercury separation device, Hg2+ can be separated and recovered by adding divalent sulfur ions to react to produce mercury sulfide precipitate, in the ammonia neutralization acid device, H2SO4 and HNO3 can be reacted with ammonia to produce ammonium sulfate and ammonium nitrate, and in the flue gas waste heat evaporation crystallization fertilizer preparation device, agricultural fertilizer is prepared by evaporation crystallization through boiler flue gas waste heat, so that the whole removal process not only has no secondary pollution, but also obtains important resources such as mercury and agricultural fertilizer, and has good development and application prospect.

[0034] Compared with the prior art, the beneficial effects of the present application are that:

[0035] ​(1) The existing free radical advanced oxidation removal of flue gas multi-pollutant technology in this field generally has various shortcomings. For example, the high-energy free radical activation removal technologies such as electrochemistry, ultraviolet light, microwave and ultrasonic wave have the disadvantages of low energy utilization efficiency and low free radical activation efficiency. The thermal activation removal technology has the problems of low free radical yield and low pollutant removal efficiency. The transition metal ion activation removal technology has the problems of difficult recovery of metal ions and secondary pollution. The transition metal oxide activation removal technology has the advantages of simple process and low device requirement, and the metal oxide catalyst can be recycled. However, the common transition metal oxide catalysts mainly include iron oxide, copper oxide, manganese oxide, cobalt oxide and cerium oxide, and mixed metal oxides of the above-mentioned metals. However, these transition metal oxides are all basic oxides, which are easy to be corroded and decomposed in an acidic solution (the oxidation removal product of the process is sulfuric acid and nitric acid), and then poisoned and deactivated, resulting in high application cost. The present application uses seaweed porous carbon to replace the traditional transition metal oxide to activate free radicals to remove flue gas pollutants, which can effectively overcome the problems of easy decomposition and deactivation of metal oxides in acidic solution and metal ion leakage, and has the advantages of wide source of seaweed biochar raw materials and easy treatment of deactivated catalyst, and has good technical and economic advantages.

[0036] (2) The existing activator modification technology and process usually have a complex modification process and device, resulting in a long process and complex device, and thus causing huge initial investment and operating cost. Therefore, developing an energy-saving low-carbon modification technology and process with low energy consumption, low cost and short process is an important research topic and development direction in the field. The multiple radiation coupling modification reactor developed in the present application can realize multi-stage continuous modification in one reactor, has the advantages of simple modification device and short process, and has good industrial prospects.

[0037] (3) Solid catalyst activated peroxymonosulfate composite salt induced free radical oxidation removal of SO2, NO and Hg in flue gas x and Hg 0It is a gas-liquid-solid three-phase reaction process. In the complex heterogeneous reaction process, the oxidation rate of free radicals is often extremely fast, so the mass transfer process is usually the rate-controlling step of the entire removal process. How to simply and efficiently strengthen the mass transfer process is the key to achieving efficient pollutant removal. However, the mass transfer efficiency of the common bubble bed reactor and spray tower reactor in this field is low, which cannot meet the requirements of industrial applications. The sound-light coupling pump jet reactor developed by the present application has extremely high performance of strengthening mixing and mass transfer (for example, the jet device can greatly strengthen the macroscopic mixing of the medium in the reactor, and the ultrasonic wave can strengthen the microscopic mixing of the medium through cavitation effect, and the synergistic effect of the two can further improve the mass transfer efficiency of the multiphase reaction), which can greatly promote the progress of the heterogeneous removal process, and further realize higher pollutant removal efficiency (the removal efficiency of the three pollutants can all achieve 100%).

[0038] In summary, the modified and removed system developed by the present application has the outstanding comprehensive advantages of simple and compact structure, short process flow, high mass transfer efficiency, high pollutant simultaneous removal efficiency and green and environmentally friendly process, and is a new type of flue gas purification method and system with broad application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 It is a structure diagram of a system for preparing seaweed porous carbon activated free radical flue gas purification.

[0040] Figure 2 It is a schematic diagram of the arrangement and size of the microwave radiator.

[0041] Figure 3 It is a schematic diagram of the arrangement and size of the gas-solid nozzle.

[0042] Figure 4 It is a schematic diagram of the arrangement and size of the ultraviolet lamp tube and ultrasonic wave emitter.

[0043] Figure 5 It is a schematic diagram of the arrangement and size of the high-speed jet device.

[0044] Figure reference numerals: 1. Impact mixer 2. Gas-solid nozzle 3. Multi-radiation coupled modification reactor 3-1. Side wall of multi-radiation coupled modification reactor 3-2. Bottom wall of multi-radiation coupled modification reactor 4. Microwave radiator 5. H2O2 storage tower 6. Urea storage tower 7. H2O2 atomizing nozzle 8. Urea atomizing nozzle 9. Corona discharge emitter 10. Vacuum ultraviolet lamp 11. Reheat device 12. Transport fan 13. Acousto-optic coupled pump-jet reactor 13-1. Wall of acoustic-optic coupled pump-jet reactor 14. High-speed jet injector 15. Ultraviolet lamp 15-1. 185nm vacuum ultraviolet lamp 15-2. 254nm short-wave ultraviolet lamp 16. Ultrasonic emitter 17. Gas distribution device 18. Demister 19. Liquid-solid rapid separation device 20. Solution replenishment device 2 1. Solution Pump One 22. Solution Pump Two 23. Solution Pump Three a. Impact Mixer Air Inlet b. Impact Mixer Biochar Left Inlet c. Impact Mixer Biochar Right Inlet d. Multiple Radiation Coupled Modification Reactor Biochar Inlet e. Multiple Radiation Coupled Modification Reactor Biochar Outlet f. Reheat Unit Outlet g. Acousto-Optical Coupled Pump-Jet Reactor Biochar Inlet h. Acousto-Optical Coupled Pump-Jet Reactor Flue Gas Outlet i. Acousto-Optical Coupled Pump-Jet Reactor Solution Discharge Port j. Liquid-Solid Rapid Separation Device Waste Liquid Discharge Port k. Liquid-Solid Rapid Separation Device Biochar Discharge Port l. Liquid-Solid Rapid Separation Device Solution Circulation Outlet m. Solution Replenishment Device Circulation Liquid Inlet n. Solution Replenishment Device Replenishment Liquid Inlet o. Solution Replenishment Device Solution Outlet p. Acousto-Optical Coupled Pump-Jet Reactor Solution Inlet q. Acousto-Optical Coupled Pump-Jet Reactor Flue Gas Inlet Detailed Implementation

[0045] 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.

[0046] like Figure 1 As shown, a flue gas purification system for preparing seaweed porous carbon activated free radicals includes a multi-radiation coupled modification reactor 3 for seaweed biochar modification and an acoustic-optical coupled pump-jet reactor 13 for inducing free radical desulfurization, denitrification and mercury removal.

[0047] Multiple microwave emitters 4 are installed on the inner sidewall of the multi-radiation coupled modification reactor 3. The first modification zone A1 is located below the multi-radiation coupled modification reactor 3 and contains multiple H2O2 atomizing nozzles 7, which are connected to the H2O2 storage tower 5. The modification zone A2 is located above the multi-radiation coupled modification reactor 3 and contains two coupling modification devices: a corona discharge emitter 9 and a vacuum ultraviolet lamp tube 10.

[0048] A second modification zone A2 is provided below the urea atomizing nozzle 8, and the urea atomizing nozzle 8 is connected with the urea storage tower 6. The multi-radiation coupling modification reactor 3 is provided at the bottom with a set of gas-solid nozzles 2 for spraying seaweed biochar. The multi-radiation coupling modification reactor 3 is connected at the bottom with the impingement mixer 1 and at the top with the reheating device 11. The multi-radiation coupling modification reactor 3 is provided with a multi-radiation coupling modification reactor biochar inlet d and a multi-radiation coupling modification reactor biochar outlet e.

[0049] The inside of the acousto-optic coupling pump jet reactor 13 is provided with a high-speed jet device 14, a vacuum ultraviolet lamp tube 15, an ultrasonic transmitter 16, a gas distribution device 17 and a mist eliminator 18. The acousto-optic coupling pump jet reactor 13 is provided at the top with an acousto-optic coupling pump jet reactor flue gas outlet h, at the bottom with an acousto-optic coupling pump jet reactor flue gas inlet q, at the lower side with an acousto-optic coupling pump jet reactor solution discharge port i and an acousto-optic coupling pump jet reactor solution inlet p, and at the bottom of the left side with an acousto-optic coupling pump jet reactor biochar inlet g, and is connected with the reheating device outlet f of the reheating device 11 through a pipeline, and a conveying fan 12 for conveying modified biochar is arranged on the connecting pipeline. The acousto-optic coupling pump jet reactor 13 is provided at the side with a liquid-solid rapid separation device 19 and a circulating system constructed by a solution supplementing device 20, which are respectively connected with the acousto-optic coupling pump jet reactor solution discharge port i and the acousto-optic coupling pump jet reactor solution inlet p through pipelines, and a solution pump one 21, a solution pump two 22 and a solution pump three 23 for conveying solution are arranged on the pipelines.

[0050] As shown in Figure 1 , the liquid-solid rapid separation device 19 is connected with the acousto-optic coupling pump jet reactor solution discharge port i, and the liquid-solid rapid separation device 19 is further provided with a liquid-solid rapid separation device waste liquid discharge port j, a liquid-solid rapid separation device biochar discharge port k and a liquid-solid rapid separation device solution circulating outlet l. The liquid-solid rapid separation device solution circulating outlet l is connected with the solution supplementing device supplementing liquid inlet m of the solution supplementing device 20, the liquid-solid rapid separation device biochar discharge port k is connected with the impingement mixer biochar left inlet b and the impingement mixer biochar right inlet c of the multi-radiation coupling modification reactor 3, and the waste liquid is discharged through the liquid-solid rapid separation device waste liquid discharge port j.

[0051] As shown in Figure 2 , a plurality of microwave radiators 4 are arranged on the wall surfaces on the left and right sides of the first modification zone A1 below the multi-radiation coupling modification reactor 3, and the microwave radiators are arranged in an orderly manner. The transverse and longitudinal spacings M1 between each microwave radiator 4 are both between 15cm and 60cm, and the transverse and longitudinal spacings are kept the same. The longitudinal and transverse spacings N1 between the gas-solid nozzles at the bottom of the multi-radiation coupling modification reactor 3 are equal and are both between 10cm and 40cm.

[0052] As shown in Figure 1As shown, the multiple radiation coupling modification reactor 3 is provided with a first modification zone A1 and a second modification zone A2, and the first modification zone A1 is located below the second modification zone A2. The height H1 of the first modification zone A1 is between 100 cm and 400 cm, and the height H1 of the second modification zone A2 is between 60 cm and 200 cm.

[0053] As shown in the figure, Figure 5 the inside wall of the acoustic-optic coupling pump jet reactor 13 is provided with a plurality of high-speed jet devices 14. The high-speed jet devices 14 are arranged at an angle of 45 degrees on the same circumference, and the high-speed jet devices arranged opposite each other are on the same axis (i.e. on the diameter line passing through the origin). The high-speed jet devices 14 are arranged in multiple layers from top to bottom, and the longitudinal spacing H3 between each layer is maintained between 60 cm and 100 cm. The initial speed of the high-speed jet devices 14 is between 20.0 m / s and 120 m / s, so as to ensure sufficient impact crushing strength and medium mixing efficiency.

[0054] As shown in the figure, Figure 4 the ultraviolet lamp tubes and the ultrasonic wave emitters in the acoustic-optic coupling pump jet reactor 13 are arranged in sequence with intervals, and the adjacent two sides of the ultrasonic wave emitters are arranged with a 185 nm vacuum ultraviolet lamp tube 15-1 and a 254 nm short wave ultraviolet lamp tube 15-2 in sequence (i.e. the ultrasonic wave emitters-185 nm vacuum ultraviolet lamp-254 nm short wave ultraviolet lamp are arranged in sequence. The ultraviolet lamp tubes and the ultrasonic wave emitters are arranged on the same concentric circle line with the same radial spacing J1, and the optimal range of J1 is between 5 cm and 40 cm, and the arc line spacing (C1, D1, E1) of the ultraviolet lamp tubes or the ultrasonic wave emitters on each arc is kept the same.

[0055] The microwave radiation power density inside the first modification zone A1 needs to be maintained between 500 W / m 3 and 4000 W / m 3 , the power of the corona discharge emitter inside the second modification zone A2 needs to be maintained between 100 W / m 3 and 800 W / m 3 , and the power of the vacuum ultraviolet light tube needs to be maintained between 40 W / m 3 and 200 W / m 3 .

[0056] The molar concentration of H2O2 sprayed by the H2O2 atomizing nozzle 7 in the multiple radiation coupling modification reactor 3 needs to be maintained between 0.5 mol / L and 2.5 mol / L, and the molar concentration of the urea solution sprayed by the urea atomizing nozzle 8 needs to be maintained between 0.01 mol / L and 2.0 mol / L.

[0057] As shown in the figure, Figure 3As shown, the gas-solid nozzle 2 of the modified seaweed biochar is arranged on the bottom wall 3-2 of the multiple radiation coupling modified reactor 3 of the multiple radiation coupling modified reactor 3, and the gas-solid nozzle 2 is arranged in sequence, and the transverse spacing and longitudinal spacing N1 of the gas-solid nozzle 2 are equal.

[0058] The peroxymonosulfate optimal concentration range of the simultaneous desulfurization, denitrification and mercury removal in the acousto-optic coupling pump jet reactor 13 is 0.02mol / L-2.5mol / L, the optimized solution pH is 0.05-6.5, the optimized reaction temperature is 30℃-80℃, and the optimized modified seaweed biochar dosage is 50mg / L-600mg / L.

[0059] The ultraviolet light tubes in the acousto-optic coupling pump jet reactor 13 adopt the cross arrangement of vacuum ultraviolet light (center wavelength 185nm) and short wave ultraviolet light (center wavelength 254nm), and the ultraviolet light tube power in the acousto-optic coupling pump jet reactor 13 needs to be kept between 50W / m 3 180W / m 3 . The ultraviolet light tube power in the acousto-optic coupling pump jet reactor 13 needs to be kept between 50W / m 3 180W / m 3 .

[0060] The optimized initial concentration ranges of flue gas pollutants SO2, NO x and Hg 0 are 100-6000ppm, 100-1800ppm and 40μg / m 3 800μg / m 3 respectively. The optimized particle size of the modified seaweed biochar is 0.002μm-0.8μm.

[0061] A method for preparing seaweed porous carbon activated free radicals for simultaneous desulfurization, denitrification and mercury removal based on multiple high-energy radiations: the operation process of the biochar modification and pollutant removal system is as follows:

[0062] I. Air enters the impinging mixer 1 from the impinging mixer air inlet a, half of the seaweed biochar enters the impinging mixer 1 from the impinging mixer biochar left inlet b, and the other half of the seaweed biochar enters the impinging mixer 1 from the impinging mixer biochar left inlet c. The opposite impingement of the two biochar streams can generate intense mixing and suspension, and then enter the multiple radiation coupling modification reactor 3 through the multiple radiation coupling modification reactor biochar inlet d under the air entrainment. The H2O2 atomizing nozzle 7 starts to spray the atomized H2O2 solution into the first modification zone A1. The microwave radiator 4 arranged in the first modification zone A1 starts to emit microwaves, and cooperates with H2O2 to induce free radical activation to modify the seaweed biochar. Through the synergistic effect of microwaves and H2O2, the seaweed biochar can be rapidly expanded and the specific surface area can be improved, and the generated free radicals can also induce the generation of abundant oxygen-containing functional groups on the surface of the seaweed biochar. The seaweed porous carbon preliminarily modified in the first modification zone A1 continues to enter the second modification zone A2. The urea atomizing nozzle 8 sprays atomized urea solution of a certain concentration as a modified nitrogen source, and the corona discharge emitter 9 and the vacuum ultraviolet lamp tube 10 cooperate to induce oxygen-containing and nitrogen-containing active components to modify the surface of the seaweed porous carbon, and further form oxygen-containing and nitrogen-containing active functional groups on the surface of the biochar.

[0063] II. The seaweed biochar modified in the multiple radiation coupling modification reactor 3 enters the reheating device 11 from the multiple radiation coupling modification reactor biochar outlet e to avoid biochar condensation and agglomeration, and then is transported by the transport fan 12 to the acousto-optic coupling pump jet reactor 13 to perform free radical activation and pollutant removal reactions. The modified seaweed porous carbon enters the acousto-optic coupling pump jet reactor 13 from the acousto-optic coupling pump jet reactor biochar inlet g, and cooperates with the ultraviolet light emitted by the vacuum ultraviolet lamp tube 15 and the ultrasonic waves emitted by the ultrasonic wave emitter 16 to activate the potassium peroxymonosulfate complex salt to induce free radical oxidation to remove pollutants. During the free radical activation and pollutant removal reaction, the high-speed jet device 14 starts the jet mode, which can realize efficient mixing of gas-liquid-solid. Ultraviolet light can cooperate with seaweed porous carbon to induce more highly active free radicals, and ultrasonic waves can strengthen the mass transfer rate of heterogeneous reactions through cavitation, and also can realize the removal of products on the surface / inside of the pores of the seaweed porous carbon, thereby realizing the multiple synergies of free radical activation, multiphase mass transfer and catalyst cleaning, and achieving mutual promotion.

[0064] III. The flue gas from the boiler enters the acousto-optic coupling pump jet reactor 13 from the acousto-optic coupling pump jet reactor flue gas inlet q, and enters the reaction zone after bubbling through the gas distribution device 17 to mix with the potassium peroxymonosulfate complex salt solution. In the potassium peroxymonosulfate complex salt solution in the reaction zone, the modified seaweed porous carbon activates the free radicals / active components (such as SO4 - ·, ·OH and O21 SO2, NO x and Hg 0 in the flue gas are oxidized and removed, and SO2, NO x and Hg 0 are oxidized to H2SO4, HNO3 and Hg 2+ respectively, so as to achieve simultaneous removal of multiple pollutants. The clean flue gas after removal is separated from the solution by the demister 18, and then sent from the sound-light coupling pump jet reactor flue gas outlet h to the tail end of the chimney and discharged into the atmosphere. The reaction waste solution can be discharged by the solution pump 21 into the liquid-solid rapid separation device 19 to separate the solution and the porous carbon of seaweed. The separated waste porous carbon of seaweed can be sent by the liquid-solid rapid separation device biochar discharge port k to the multiple radiation coupling modification reactor 3 through the impingement mixer biochar left inlet b and the impingement mixer biochar right inlet c for further modification and regeneration. The separated solution passes through the liquid-solid rapid separation device solution circulation outlet 1, and is discharged by the solution pump 22 into the solution supplementing device 20, and then after supplementing with new potassium hydrogen peroxymonosulfate composite salt solution, is sent through the solution supplementing device solution outlet o into the sound-light coupling pump jet reactor 13 to participate in the oxidation and removal reaction. The newly supplemented potassium hydrogen peroxymonosulfate composite salt solution is sent into the solution supplementing device 20 through the solution supplementing device supplementing liquid inlet n. After multiple cycles, the saturated waste solution containing H2SO4, HNO3 and Hg 2+ is discharged through the liquid-solid rapid separation device waste liquid discharge port j and sent to the tail end of the multi-stage comprehensive resource utilization system.

[0065] IV. The multi-stage comprehensive resource utilization system comprises a mercury separation device, an ammonia neutralization acid device and a flue gas waste heat evaporation crystallization fertilizer preparation device. In the mercury separation device, Hg 2+ can be separated and recovered by adding divalent sulfur ions to produce mercury sulfide precipitate, in the ammonia neutralization acid device, H2SO4 and HNO3 can be reacted with ammonia to produce ammonium sulfate and ammonium nitrate, and in the flue gas waste heat evaporation crystallization fertilizer preparation device, agricultural fertilizer is prepared by evaporation crystallization of boiler flue gas waste heat, so that the whole removal process not only has no secondary pollution, but also obtains important resources such as mercury and agricultural fertilizer, and has good development and application prospect.

[0066] The following are examples of simultaneous removal of SO2, NO x and Hg 0 by the device under different conditions:

[0067] Example 1:

[0068] The lateral and longitudinal spacing M1 between the microwave radiators in the multi-radiation coupling modification reactor is 30 cm, the height H1 of the modification zone (A1) is 100 cm, and the height H2 of the modification zone (A2) is 80 cm. The initial speed of the high-speed jet is 60 m / s, and the longitudinal spacing between each high-speed jet is 40 cm. The microwave radiation power density in the modification zone (A1) of the multi-radiation coupling modification reactor is 600 W / m 3 , the power of the corona discharge emitter in the modification zone (A2) is 100 W / m 3 , and the power of the vacuum ultraviolet lamp is 80 W / m 3 . The concentration of the H2O2 solution is 0.1 mol / L, and the concentration of the urea solution is 0.05 mol / L. The concentration of the potassium hydrogen sulfate composite salt solution in the acousto-optic coupling pump jet reactor is 0.05 mol / L, the pH of the reaction solution is 2.3, the reaction temperature is 65°C, the dosage of the modified seaweed porous carbon is 120 mg / L, and the particle size of the modified biochar is 0.02 μm-0.08 μm. The concentrations of SO2, NO x , and Hg 0 in the flue gas are 1600 ppm, 350 ppm, and 60 μg / m 3 , respectively.

[0069] The preliminary results of numerical simulation and experimental pilot test are as follows: the simultaneous removal efficiencies of SO2, NO x , and Hg 0 in the flue gas can reach 90.1%, 49.9%, and 62.4%, respectively.

[0070] Example 2:

[0071] The lateral and longitudinal spacing M1 between the microwave radiators in the multi-radiation coupling modification reactor is 30 cm, the height H1 of the modification zone (A1) is 100 cm, and the height H2 of the modification zone (A2) is 80 cm. The initial speed of the high-speed jet is 60 m / s, and the longitudinal spacing between each high-speed jet is 40 cm. The microwave radiation power density in the modification zone (A1) of the multi-radiation coupling modification reactor is 800 W / m 3 , the power of the corona discharge emitter in the modification zone (A2) is 100 W / m 3 , and the power of the vacuum ultraviolet lamp is 100 W / m 3 . The concentration of the H2O2 solution is 0.1 mol / L, and the concentration of the urea solution is 0.05 mol / L. The concentration of the potassium hydrogen sulfate composite salt solution in the acousto-optic coupling pump jet reactor is 0.1 mol / L, the pH of the reaction solution is 2.3, the reaction temperature is 65°C, the dosage of the modified seaweed porous carbon is 160 mg / L, and the particle size of the modified biochar is 0.02 μm-0.08 μm. The concentrations of SO2, NO xWith Hg 0 The concentrations were 1600 ppm, 350 ppm and 60 μg / m³, respectively. 3 .

[0072] Preliminary results from numerical simulations and small-scale experiments show that SO2 and NO in the flue gas... x With Hg 0 The removal efficiencies can reach 93.4%, 57.8%, and 69.7%, respectively.

[0073] Example 3:

[0074] In the multi-radiation coupled modification reactor, the lateral and longitudinal spacing M1 between microwave radiators is 30 cm. The height H1 of the modification zone (A1) is 100 cm, and the height H2 of the modification zone (A2) is 80 cm. The initial velocity of the high-speed jets is 60 m / s, and the longitudinal spacing between each high-speed jet is 40 cm. The microwave radiation power density in the modification zone (A1) of the multi-radiation coupled modification reactor is 800 W / m². 3 The power of the corona discharge emitter in the modified zone (A2) is 150W / m. 3 The power of the vacuum ultraviolet lamp tube is 100W / m 3 The concentration of H2O2 solution was 0.1 mol / L, and the concentration of urea solution was 0.05 mol / L. The concentration of potassium persulfate composite salt solution added to the acoustic-optical coupled pump-jet reactor was 0.15 mol / L, the pH of the reaction solution was 2.3, the reaction temperature was 65℃, the dosage of modified seaweed porous carbon was 200 mg / L, and the particle size of the modified biochar was 0.02 μm–0.08 μm. SO2 and NO in the flue gas... x With Hg 0 The concentrations were 1600 ppm, 350 ppm and 60 μg / m³, respectively. 3 .

[0075] Preliminary results from numerical simulations and small-scale experiments show that SO2 and NO in the flue gas... x With Hg 0 The removal efficiencies can reach 99.5%, 68.8%, and 77.4%, respectively.

[0076] Example 4:

[0077] In the multi-radiation coupled modification reactor, the lateral and longitudinal spacing M1 between microwave radiators is 30 cm. The height H1 of the modification zone (A1) is 100 cm, and the height H2 of the modification zone (A2) is 80 cm. The initial velocity of the high-speed jets is 60 m / s, and the longitudinal spacing between each high-speed jet is 40 cm. The microwave radiation power density in the modification zone (A1) of the multi-radiation coupled modification reactor is 800 W / m². 3, the power of the corona discharge emitter in the modification zone (A2) is 150 W / m 3 , the power of the vacuum ultraviolet lamp in the modification zone (A2) is 150 W / m 3 . The concentration of the H2O2 solution is 0.2 mol / L, and the concentration of the urea solution is 0.05 mol / L. The concentration of the potassium peroxymonosulfate composite salt solution in the acousto-optic coupling pump jet reactor is 0.2 mol / L, the pH of the reaction solution is 2.3, the reaction temperature is 65°C, the modified seaweed porous carbon dosage is 240 mg / L, and the particle size of the modified biochar is 0.02 μm-0.08 μm. The concentrations of SO2, NO x , and Hg 0 in the flue gas are 1600 ppm, 350 ppm, and 60 μg / m 3 , respectively.

[0078] The preliminary results of numerical simulation and experimental pilot test are as follows: the simultaneous removal efficiencies of SO2, NO x , and Hg 0 in the flue gas can reach 100%, 77.5%, and 83.5%, respectively.

[0079] Example 5:

[0080] The lateral and longitudinal spacings M1 between the microwave radiators in the multi-radiation coupling modification reactor are both 30 cm, the height H1 of the modification zone (A1) is 100 cm, and the height H2 of the modification zone (A2) is 80 cm. The initial velocity of the high-speed jet is 60 m / s, and the longitudinal spacing between each high-speed jet is 40 cm. The microwave radiation power density in the modification zone (A1) of the multi-radiation coupling modification reactor is 800 W / m 3 , the power of the corona discharge emitter in the modification zone (A2) is 150 W / m 3 , and the power of the vacuum ultraviolet lamp in the modification zone (A2) is 150 W / m 3 . The concentration of the H2O2 solution is 0.2 mol / L, and the concentration of the urea solution is 0.1 mol / L. The concentration of the potassium peroxymonosulfate composite salt solution in the acousto-optic coupling pump jet reactor is 0.25 mol / L, the pH of the reaction solution is 2.3, the reaction temperature is 65°C, the modified seaweed porous carbon dosage is 280 mg / L, and the particle size of the modified biochar is 0.02 μm-0.08 μm. The concentrations of SO2, NO x , and Hg 0 in the flue gas are 1600 ppm, 350 ppm, and 60 μg / m 3 , respectively.

[0081] The preliminary results of numerical simulation and experimental pilot test are as follows: the simultaneous removal efficiencies of SO2, NO x , and Hg 0The simultaneous removal efficiencies of SO2, NO and Hg can reach 100%, 90.4% and 98.1% respectively.

[0082] Embodiment 6

[0083] The lateral spacing and longitudinal spacing M1 between the microwave radiators in the multi-radiation coupling modification reactor are both 30 cm, the height H1 of the modification zone (A1) is 100 cm, and the height H2 of the modification zone (A2) is 80 cm. The initial speed of the high-speed jet is 60 m / s, and the longitudinal spacing between each high-speed jet is 40 cm. The microwave radiation power density in the modification zone (A1) of the multi-radiation coupling modification reactor is 800 W / m 3 , the corona discharge emitter power in the modification zone (A2) is 150 W / m 3 , and the vacuum ultraviolet lamp power is 150 W / m 3 . The concentration of the H2O2 solution is 0.3 mol / L, and the concentration of the urea solution is 0.1 mol / L. The potassium hydrogen sulfate composite salt solution is added to the acousto-optic coupling pump jet reactor at a concentration of 0.25 mol / L, the pH of the reaction solution is 2.3, the reaction temperature is 65 DEG C, the modification seaweed porous carbon is added at a dosage of 320 mg / L, and the particle size of the modified biochar is 0.02-0.08 um. The concentrations of SO2, NO x and Hg 0 in the flue gas are 1600 ppm, 350 ppm and 60 ug / m 3 respectively.

[0084] The preliminary results of numerical simulation and experimental pilot test are as follows: the simultaneous removal efficiencies of SO2, NO x and Hg 0 in the flue gas can reach 100%, 100% and 100% respectively.

[0085] The maximum simultaneous removal efficiencies of SO2, NO x and Hg 0 in the method of the present application can reach 100%, 100% and 100% respectively, which has extremely high simultaneous removal efficiency of multiple pollutants, can realize simultaneous removal of single or multiple flue gas pollutants, and no waste water or waste liquid is generated, which can well meet the current strict ultra-low emission requirements, and has extremely significant technical competitive advantage.

[0086] The embodiments are preferred embodiments of the present application, but the present application is not limited to the above embodiments, and any obvious improvement, replacement or modification made by those skilled in the art without departing from the essential content of the present application shall fall within the protection scope of the present application.

Claims

1. A system for flue gas purification by activated radicals prepared from seaweed porous carbon, characterized in that, The system comprises a multiple radiation coupling modification reactor (3) for seaweed biochar modification and an acousto-optic coupling pump jet reactor (13) for inducing free radical desulfurization, denitrification and demercuration; the multiple radiation coupling modification reactor (3) is internally divided into a first modification zone (A1) and a second modification zone (A2); the first modification zone (A1) is located below the multiple radiation coupling modification reactor (3) and is internally provided with a plurality of H2O2 atomizing nozzles (7) connected with an H2O2 storage tower (5), and a plurality of microwave radiators (4) are arranged on the side wall surface of the H2O2 atomizing nozzles (7); the second modification zone (A2) is located above the multiple radiation coupling modification reactor (3) and is internally provided with a corona discharge emitter (9) and a first vacuum ultraviolet lamp tube (10); a urea atomizing nozzle (8) is arranged below the second modification zone (A2) and is connected with a urea storage tower (6); a gas-solid nozzle (2) for spraying seaweed biochar is arranged at the bottom of the multiple radiation coupling modification reactor (3); the acousto-optic coupling pump jet reactor (13) is internally provided with a high-speed jet device (14), a second vacuum ultraviolet lamp tube (15), an ultrasonic emitter (16), a gas distribution device (17) and a demister (18); the acousto-optic coupling pump jet reactor (13) is provided with an acousto-optic coupling pump jet reactor flue gas inlet (q) at the bottom, an acousto-optic coupling pump jet reactor flue gas outlet (h) at the top, an acousto-optic coupling pump jet reactor solution discharge port (i) and an acousto-optic coupling pump jet reactor solution inlet (p) at the lower side, and an acousto-optic coupling pump jet reactor biochar inlet (g) at the bottom of the left side; a circulation system constructed by a liquid-solid rapid separation device (19) and a solution supplementing device (20) is arranged on the side of the acousto-optic coupling pump jet reactor (13) and is connected with the acousto-optic coupling pump jet reactor solution discharge port (i) and the acousto-optic coupling pump jet reactor solution inlet (p) through pipelines, and the acousto-optic coupling pump jet reactor solution is potassium monopersulfate solution.

2. A system for flue gas cleaning by activated radicals of porous carbon prepared from seaweed according to claim 1, characterized in that, The bottom of the multiple radiation coupling modification reactor (3) is provided with a multiple radiation coupling modification reactor biochar inlet (d) connected with an impingement mixer (1); the top of the multiple radiation coupling modification reactor (3) is provided with a multiple radiation coupling modification reactor biochar outlet (e); the multiple radiation coupling modification reactor biochar outlet (e) is connected with a reheating device (11), and the outlet (f) of the reheating device is connected with the acousto-optic coupling pump jet reactor biochar inlet (g) through a pipeline.

3. A system for flue gas purification by activated radicals of porous carbon prepared from seaweed according to claim 2, characterized in that, The pipeline connecting the reheat device outlet (f) and the sound-light coupling pump jet reactor biochar inlet (g) is provided with a conveying fan (12); the pipeline connecting the sound-light coupling pump jet reactor solution discharge port (i) and the liquid-solid rapid separation device (19) is provided with a solution pump one (21), the pipeline connecting the liquid-solid rapid separation device (19) and the solution supplementing device (20) is provided with a solution pump two (22); the pipeline connecting the sound-light coupling pump jet reactor solution inlet (p) and the solution supplementing device (20) is provided with a solution pump three (23).

4. A system for flue gas cleaning by activated radicals of porous carbon prepared from seaweed according to claim 1, characterized in that, The height H1 of the first modification zone (A1) is between 100 cm and 400 cm; the height H2 of the second modification zone (A2) is between 60 cm and 200 cm, the microwave radiation power density inside the first modification zone (A1) is kept between 500 W / m 3 ~4000 W / m 3 , the corona discharge emitter power inside the second modification zone (A2) is kept between 100 W / m 3 ~800 W / m 3 , the vacuum ultraviolet lamp power is kept between 40 W / m 3 ~200 W / m 3 ; a plurality of microwave radiators (4) are arranged on the wall surface of the first modification zone (A1), the microwave radiators (4) are arranged in an order, the horizontal and vertical spacing M1 between each microwave radiator (4) is between 15 cm and 60 cm, and the horizontal and vertical spacing is kept the same; the horizontal and vertical spacing N1 between the gas-solid nozzles (1) is equal, and is between 10 cm and 40 cm.

5. A system for flue gas cleaning by activated radicals of porous carbon prepared from seaweed according to claim 1, characterized in that, The high-speed jet flow device (14) is arranged at an angle of 45 degrees on the same circumference, and the high-speed jet flow devices arranged oppositely are on the same axis, the high-speed jet flow device (14) is arranged in multiple layers from top to bottom, and the longitudinal spacing H3 between each layer is kept between 60 cm and 100 cm, and the initial speed of the high-speed jet flow device (14) is between 20 m / s and 120 m / s.

6. A system for flue gas cleaning by activated radicals of porous carbon prepared from seaweed according to claim 1, characterized in that, The ultraviolet lamp and the ultrasonic wave emitter in the sound-light coupling pump jet reactor (13) are arranged in sequence and at intervals, and the two adjacent sides of the ultrasonic wave emitter are arranged with a 185 nm vacuum ultraviolet lamp and a 254 nm short wave ultraviolet lamp in sequence; the ultraviolet lamp and the ultrasonic wave emitter are arranged on the same concentric circle with the same radial spacing J1, J1 is between 5 cm and 40 cm, and the arc spacing of the ultraviolet lamp or the ultrasonic wave emitter on each arc is kept the same.

7. A system for flue gas cleaning by activated radicals of porous carbon prepared from seaweed according to claim 1, characterized in that, The H2O2 molar concentration sprayed by the H2O2 atomizing nozzle (7) in the multiple radiation coupling modification reactor (3) is kept between 0.5 mol / L and 2.5 mol / L, and the molar concentration of the urea solution sprayed by the urea atomizing nozzle (8) is kept between 0.01 mol / L and 2.0 mol / L.

8. A system for flue gas cleaning by activated radicals prepared from seaweed porous carbon according to claim 1, characterized in that, The concentration of potassium peroxymonosulfate in the acousto-optic coupling pump jet reactor (13) is 0.02 mol / L to 2.5 mol / L, the pH of the solution is 0.05 to 6.5, the reaction temperature is 30°C to 80°C, and the modified seaweed biochar dosage is 50 mg / L to 600 mg / L; the power of the ultraviolet lamp tube in the acousto-optic coupling pump jet reactor (13) is kept between 50 W / m 3 ~180 W / m 3 ; the power of the ultrasonic emitter in the acousto-optic coupling pump jet reactor (13) is kept between 100 W / m 3 ~400 W / m 3 .

9. The system for purification of flue gas by activated radicals of seaweed porous carbon according to claim 1, wherein, The initial concentration ranges of the flue gas pollutants SO2, NO x and Hg 0 are respectively 100 ~ 6000 ppm, 100 ~ 1800 ppm and 40 μg / m 3 ~ 800 μg / m 3 ; the particle size of the modified seaweed biochar is 0.002 μm ~ 0.8 μm.

10. A method for preparing a smoke gas purification system of activated radicals of porous carbon of seaweed according to any one of claims 1-9, characterized in that, The operation process of the system is as follows: I. Air enters the impingement mixer (1) from the air inlet (a) of the impingement mixer, and half of the seaweed biochar enters the impingement mixer (1) from the biochar left inlet (b) of the impingement mixer, and the other half of the seaweed biochar enters the impingement mixer (1) from the biochar left inlet (c) of the impingement mixer; through the opposite impingement of the two biochar streams, intense mixing and suspension are generated, and then the biochar enters the multi-radiation coupling modification reactor (3) through the biochar inlet (d) of the multi-radiation coupling modification reactor under the air carrying; the H2O2 atomizing nozzle (7) starts to spray the atomized H2O2 solution into the first modification zone (A1); the microwave radiator (4) arranged in the first modification zone (A1) emits microwaves, and cooperates with H2O2 to induce free radical activated modification of seaweed biochar; through the cooperation of microwaves and H2O2, the seaweed biochar can be rapidly expanded and the specific surface area can be improved, and the generated free radicals can also generate abundant oxygen-containing functional groups on the surface of the seaweed biochar; the seaweed porous carbon preliminarily modified in the first modification zone (A1) continues to enter the modification zone (A2); the urea atomizing nozzle (8) sprays atomized urea solution as a modified nitrogen source, and the corona discharge emitter (9) and the first vacuum ultraviolet lamp tube (10) cooperate to induce oxygen-containing and nitrogen-containing active components to modify the surface of the seaweed porous carbon, and further form oxygen-containing and nitrogen-containing active functional groups on the surface of the biochar; II. The modified seaweed biochar in the multi-radiation coupling modification reactor (3) enters the reheating device (11) through the biochar outlet (e) of the multi-radiation coupling modification reactor to avoid biochar condensation and agglomeration, and then is transported by the transport fan (12) to the acousto-optic coupling pump jet reactor (13) to implement free radical activation and pollutant removal reaction; the modified seaweed porous carbon enters the acousto-optic coupling pump jet reactor (13) through the biochar inlet (g) of the acousto-optic coupling pump jet reactor, and cooperates with the ultraviolet light emitted by the second vacuum ultraviolet lamp tube (15) and the ultrasonic wave emitted by the ultrasonic wave emitter (16) to activate the potassium hydrogen persulfate complex salt to induce free radical oxidation and remove pollutants; during the free radical activation and pollutant removal reaction, the high-speed jet device (14) starts the jet mode to realize efficient mixing of gas-liquid-solid; the ultraviolet light can cooperate with the seaweed porous carbon to induce more high-activity free radicals, and the ultrasonic wave can strengthen the mass transfer rate of the heterogeneous reaction through cavitation, and also can realize the removal of products on the surface and inside of the seaweed porous carbon, realize the multi-element synergy of free radical activation, multiphase mass transfer and catalyst cleaning, and realize mutual promotion. III. The flue gas from the boiler enters the acousto-optic coupling pump jet reactor (13) from the acousto-optic coupling pump jet reactor flue gas inlet (q), and after bubbling through the air distribution device (17) enters the reaction zone and mixes with the potassium peroxymonosulfate composite salt solution; in the potassium peroxymonosulfate composite salt solution in the reaction zone, the modified seaweed porous carbon activates the potassium peroxymonosulfate composite salt induced free radicals / active components SO4 - • OH, • O and O2 1 Oxidation removal reaction with SO2, NO x and Hg 0 in the flue gas, and SO2, NO x and Hg 0 are oxidized to H2SO4, HNO3 and Hg 2+ respectively, achieving simultaneous removal of multiple pollutants; the clean flue gas after removal is sent into the chimney in the tail part from the acousto-optic coupling pump jet reactor flue gas outlet (h) after separation and removal of the solution by the demister (18), and is discharged into the atmosphere; the reaction waste solution can be discharged into the liquid-solid rapid separation device (19) by the solution pump one (21) to implement separation of the solution and the seaweed porous carbon; the separated waste seaweed porous carbon can be sent into the multiple radiation coupling modification reactor (3) from the impingement mixer biochar left inlet (b) and the impingement mixer biochar right inlet (c) by the liquid-solid rapid separation device biochar discharge port (k) to implement again modification and regeneration; The separated solution is discharged into the solution supplementing device (20) by the liquid-solid rapid separation device solution circulating outlet (l) and a solution pump two (22), and then after supplementing new potassium hydrogen peroxymonosulfate composite salt solution, it is sent into the acousto-optic coupling pump jet reactor (13) by the solution supplementing device solution outlet (o) to participate in the oxidation removal reaction; the newly supplemented potassium hydrogen peroxymonosulfate composite salt solution is sent into the solution supplementing device (20) by the solution supplementing device supplementing liquid inlet (n); after multiple cycles, the saturated waste solution containing H2SO4, HNO3 and Hg 2+ is discharged through the liquid-solid rapid separation device waste liquid discharge port (j) and then sent into the tail multi-stage comprehensive resource utilization system. IV. The multi-stage comprehensive resource utilization system comprises a mercury separation device, an ammonia neutralization acid device, and a flue gas waste heat evaporation crystallization fertilizer preparation device; in the mercury separation device, Hg 2+ The mercury can be separated and recovered by adding divalent sulfur ions to produce a mercury sulfide precipitate, in the ammonia neutralization acid device, H2SO4 and HNO3 can be reacted with ammonia to produce ammonium sulfate and ammonium nitrate, and in the flue gas waste heat evaporation crystallization fertilizer preparation device, agricultural fertilizer can be prepared through flue gas waste heat evaporation crystallization.

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