CN107715667B - Flue gas demercuration method and system for exciting fly ash induced free radicals by microwave ammonium persulfate - Google Patents
Flue gas demercuration method and system for exciting fly ash induced free radicals by microwave ammonium persulfate Download PDFInfo
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Abstract
The invention relates to a flue gas demercuration method and a system for exciting fly ash induced free radicals by microwave ammonium persulfate; the system comprises a microwave spray reactor, a burner containing Hg0The flue gas enters a microwave spraying reactor after being dedusted and cooled; the fly ash is excited by microwaves to activate ammonium persulfate in a microwave spray reactor to generate hydroxyl and sulfate radical to remove Hg in smoke0Oxidizing into a divalent mercury solution; after entering a mercury separation tower, the bivalent mercury solution is separated and recovered after being added with bivalent sulfur ions to react to generate mercuric sulfide precipitate; the system can realize Hg0The removal rate is 100 percent, and the removal process has no secondary pollution and has wide market application prospect.
Description
Technical Field
The invention relates to the field of flue gas purification, in particular to a flue gas demercuration system for exciting fly ash by microwave ammonium persulfate to induce free radicals.
Background
Mercury is a highly toxic heavy metal trace element, and has great harm to human health and ecological environment. Coal-fired boilers are the largest man-made pollution source for mercury emissions. China is the first coal consuming country in the world, the proportion of coal in an energy structure is as high as 75%, and the pattern still has no great change for a long time in the future. With the increasing strictness of the environmental protection standards of the atmosphere of the coal-fired pollutants, the emergence of the mercury pollution control standards of the coal-fired flue gas is expected to be a necessary trend in the near future. Therefore, research and development of an effective coal-fired flue gas mercury pollution control method is one of the important tasks faced by the environmental protection scientists in China.
In recent years, scholars at home and abroad make a great deal of effective work in the research of new mercury removal theories and new technical fields. At present, among the numerous demercuration methods, adsorbent adsorption and wet scrubbing are considered as two of the most promising mainstream demercuration technologies in the field of coal-fired flue gas demercuration. The most studied technology in wet scrubbing and demercuration is to use the existing wet flue gas desulfurization system to carry out combined scrubbing and demercuration, and the technology can realize higher Hg2+(g) Removal rate but for poorly soluble Hg0(g) Without significant removal, some of the oxidized mercury may also be reduced to elemental mercury. A number of scholars have attempted to remove Hg from flue gas using a number of oxidation techniques prior to the desulfurization tower0(g) First oxidized to Hg2+(g) Then washing and removing Hg by a wet flue gas desulfurization system2+(g) In that respect At present, partial Hg can be realized by Selective Catalytic Reduction (SCR) catalytic oxidation demercuration which is researched more0(g) Conversion to Hg2+(g) However, the demercuration effect is obviously influenced by the components of the coal, the type of catalyst, the combustion mode and the structure of a burner, and the relevant catalytic oxidation mechanism is still not quite clear. Other oxidation techniques, such as plasma oxidation, photocatalytic oxidation, and ozone oxidation, are still in the laboratory exploration phase. Oxidizing and absorbing Hg in an absorption tower by using traditional oxidants such as potassium permanganate, potassium persulfate and sodium chlorite0(g) Good effect is achieved, but the defects that the absorbent is expensive or the product components are complex and difficult to process exist, and the related technology is to be further improved. The adsorption method is mainly characterized in that the activated carbon or other adsorbents are used for adsorbing Hg in the flue gas2+(g) And Hg0(g) Firstly, the mercury is converted into granular mercury, and then the granular mercury is captured by utilizing the existing dust removal equipment to achieve the aim of removing mercury. The activated carbon adsorption method which is researched more and has the most mature technology at present has higher demercuration efficiency, but the application cost is extremely high, and enterprises are difficult to bear. Although other adsorbents such as precious metals, metal oxides, fly ash, activated coke, calcium-based materials, molecular sieves, natural mineral materials and the like have potential development prospects, large-scale industrial application cannot be achieved at present due to the defects and the shortcomings in the aspects of application cost, mercury removal efficiency, adsorbent stability, adsorption mechanism research and the like. In summary, no coal-fired flue gas demercuration technology suitable for large-scale commercialization exists at present.
Disclosure of Invention
The invention aims to overcome the technical problems in the prior art and provides a flue gas demercuration system for exciting fly ash induced free radicals by microwave ammonium persulfate; the Hg contained from the burner0The flue gas enters a microwave spraying reactor after being dedusted and cooled, and the microwave spraying reactor is used for microwave sprayingExciting fly ash to activate ammonium persulfate in a microwave spray reactor to generate hydroxyl and sulfate radical to remove Hg in flue gas0Oxidizing the mercury into a bivalent mercury solution, adding the bivalent mercury solution into a mercury separation tower, reacting by adding bivalent sulfur ions to generate mercuric sulfide precipitate, and separating and recovering the mercuric sulfide precipitate; the system can realize Hg0The removal rate is 100 percent, and the removal process has no secondary pollution and has wide market application prospect.
The reaction process and the basic principle of the system are as follows:
(1) the Fly ash (Fly ash) is excited by Microwave (MW) to catalytically decompose ammonium persulfate to generate high-activity sulfate radicals and hydroxyl radicals. The specific reaction process can be expressed by the following equations (1) to (2). As shown in FIG. 1, we have confirmed the basic principle described above by successfully determining the generation of sulfate radicals and hydroxyl radicals in the desorption system using an electron spin resonance spectrometer.
(2) Sulfate radicals and hydroxyl radicals generated in the reactions (1) to (2) have super-strong oxidizability, and can be used for treating Hg in smoke0Will be divalent mercury. The specific procedure can be shown by the following chemical reactions (3) to (6).
·OH+Hg0→Hg++OH- (3)
·OH+Hg+→Hg2++OH- (4)
(3) The divalent mercury solution generated by the oxidation enters a mercury separation tower and then is introducedAnd adding divalent sulfur ions to react to generate mercuric sulfide precipitate, and separating and recycling. The system can realize Hg0The removal rate is 100 percent, and the removal process has no secondary pollution and has wide market application prospect.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
the invention provides a flue gas demercuration system for exciting fly ash induced radicals by microwave ammonium persulfate, which comprises a dust remover, a cooler, a fan, a flue and a chimney, wherein the dust remover, the cooler, the fan and the chimney are sequentially connected in series through the flue; the system comprises a microwave spray reactor; the microwave spraying reactor is connected with a cooler and a fan in series through a flue, and comprises a solution spraying reaction area, a cooling air inlet, a cooling air outlet, a flue gas inlet, a flue gas outlet, a total flue gas inlet, a total flue gas outlet, a cooling air total inlet, a microwave magnetron mounting area, a quartz glass partition plate, an oxidant supplementing tower and a solution pump;
the microwave spraying reactor is formed by connecting a plurality of solution spraying reaction areas in parallel, the solution spraying reaction areas and the microwave magnetron mounting areas are sequentially arranged at intervals, and the middle of each of the 2 areas is separated by a quartz glass partition plate;
the flue gas inlet and the flue gas outlet are respectively positioned at two sides of the solution spraying reaction zone; a plurality of nozzles are arranged in parallel in the middle of the solution spraying reaction zone; the nozzle is connected with an oxidant supplementing tower through a solution pump, and the oxidant is ammonium persulfate solution; the total flue gas inlet is communicated with each flue gas inlet, the total flue gas outlet is communicated with each flue gas outlet, and the total flue gas inlet and the total flue gas outlet are respectively communicated with the flue.
The cooling air inlet and the cooling air outlet are respectively positioned at two sides of the microwave magnetron mounting area; the microwave magnetron mounting area is provided with a plurality of microwave magnetrons; the cooling air inlet is respectively communicated with the cooling air main inlet and the cooling air outlet.
The bottom of the microwave spraying reactor is provided with an inclined groove, and the bottom of the inclined groove is provided with a product outlet and a circulating liquid outlet; the product outlet is connected with a mercury separation tower; the outlet of the circulating liquid is connected with an oxidant supplementing tower.
The total width W of the microwave spraying reactor is between 0.2m and 8 m; the total length L of the microwave spraying reactor is between 0.2m and 8 m; the total height H of the microwave spray reactor lies between 0.2m and 10 m.
The width b of the solution spraying reaction zone is between 0.1m and 0.6 m.
The transverse distance a between the microwave magnetrons is between 0.1m and 0.8 m; the nozzles are arranged at a transverse pitch of 2a and at a longitudinal pitch of 1.5 a.
The grain diameter of atomized liquid drops sprayed by the nozzle is not more than 80 microns, and the microwave radiation power density in the microwave spraying reactor is 20W/m3-1600W/m3。
The invention also provides a flue gas demercuration method for exciting fly ash induced free radicals by microwave ammonium persulfate, which is completed based on the microwave spraying reactor, and firstly, Hg-containing flue gas from a combustor is enabled to be discharged0The flue gas is dedusted and cooled and then enters a microwave spray reactor, and the fly ash is excited by microwaves to activate an ammonium persulfate solution in the microwave spray reactor to generate hydroxyl and sulfate radicals to remove Hg in the flue gas0Oxidizing the mercury into a bivalent mercury solution, and separating and recycling the bivalent mercury solution after the bivalent mercury solution enters a mercury separation tower and is added with bivalent sulfur ions to react to generate mercuric sulfide precipitate.
The optimal concentration of the fly ash in the flue gas is 0.2g/m3-200g/m3(ii) a The temperature in the microwave spraying reactor is controlled to be 25-160 ℃.
The effective liquid-gas ratio of the ammonium persulfate solution to the flue gas is 1-12L/m3The effective concentration of the ammonium persulfate solution is between 0.05 and 2.5mol/L, and the pH value of the solution is between 0.1 and 9.9;
hg in the flue gas0The content of (A) is not more than 1000 mu g/m3(ii) a The combustor is any one of a coal-fired boiler, an industrial kiln way or a garbage incinerator.
The microwave in the microwave spray reactor excites fly ash to activate oxidant ammonium persulfate in the microwave spray reactor to generate hydroxyl and sulfate radical to remove smokeHg in gas0Oxidizing the mercury into a bivalent mercury solution, adding the bivalent mercury solution into a mercury separation tower, reacting by adding bivalent sulfur ions to generate mercuric sulfide precipitate, and separating and recovering the mercuric sulfide precipitate; the system can realize Hg0The removal rate is 100 percent, and the removal process has no secondary pollution and has wide market application prospect.
The invention has the advantages and obvious effects that:
chinese patent (ZL201310683054.8) proposes a method and a system for removing mercury based on coupling of an ultraviolet lamp and a flue, and Chinese patent (ZL201010296592.8) proposes a flue gas mercury removal system based on photochemical advanced oxidation. Both of the above patents have been proposed by the inventor group, the greatest difference from the present invention is that both of them use ultraviolet light as the excitation source. However, it is known that the penetration distance of ultraviolet light in water is extremely short. There are reports that the effective propagation distance of 254nm short-wave ultraviolet light is only several centimeters even in pure water, which makes it difficult to enlarge the reaction apparatus. In addition, impurities such as particles existing in actual coal-fired flue gas can seriously obstruct the transmission of ultraviolet light, and further influence the safe and efficient operation of a photochemical removal system. Therefore, the above disadvantages severely restrict the industrial application of photochemical removal systems.
The microwave activation removal system can effectively overcome the technical problems. Unlike ultraviolet light, microwaves are able to penetrate solids and liquids efficiently, and the penetration distance of microwaves in solution is much longer than ultraviolet light (similar to microwave ovens heating food). In addition, microwave technology has been used in large scale in industry and daily life, with good engineering and practical experience. Therefore, the microwave activated free radical system has much higher industrial application prospect than the ultraviolet activated system. The flue gas demercuration system for exciting fly ash induced free radicals by microwave ammonium persulfate can realize Hg0The removal of 100 percent can meet the technical requirement of ultra-clean emission of the flue gas of a coal-fired boiler and a kiln newly produced in China, and has wide market development and application prospects.
Drawings
FIG. 1 is a graph showing the measurement of active radicals in a system for catalytic decomposition of ammonium persulfate by microwave-excited fly ash, in which peaks of spectra represent sulfate radicals and hydroxyl radicals;
FIG. 2 is an overall schematic of the system of the present invention;
fig. 3 is a layout (top view) of the nozzle and microwave magnetron key devices in the microwave spray reactor.
Fig. 4 is a layout view (front view) of the key devices of the nozzles and microwave magnetrons in the microwave spray reactor.
In the figure, 1-a combustor, 2-a flue, 3-a dust remover, 4-a cooler, 5-a microwave spray reactor, 6-a mercury separation tower, 7-a solution pump, 8-an oxidant supplement tower, 9-a fan and 10-a chimney; 501-a total flue gas inlet, 502-a total flue gas outlet, 503-a nozzle, 504-a microwave magnetron, 505 an inclined groove, 506-a solution, 507-a circulating liquid outlet, 508-a product outlet, 509-a cooling air total inlet, 510-a cooling air inlet, 511-a cooling air outlet, 512-a flue gas inlet, 513-a flue gas outlet, 514-a microwave spray reactor wall surface, 515-a solution spray reaction zone, 516-a microwave magnetron mounting zone and 517-a quartz glass partition plate.
Detailed Description
The invention relates to a flue gas demercuration system for exciting fly ash induced free radicals by microwave ammonium persulfate. Hg-containing from the burner0The flue gas enters a microwave spraying reactor after being dedusted and cooled. The fly ash is excited by microwaves to activate ammonium persulfate in a microwave spray reactor to generate hydroxyl and sulfate radical to remove Hg in smoke0Oxidized into a divalent mercury solution. After entering a mercury separation tower, the bivalent mercury solution is separated and recovered after being added with bivalent sulfur ions to react to generate mercury sulfide precipitate. The system can realize Hg0The removal rate is 100 percent, and the removal process has no secondary pollution and has wide market application prospect.
Example 1:
flue gas demercuration system for exciting fly ash induced free radicals by microwave ammonium persulfate: as shown in fig. 2, 3 and 4, the flue gas demercuration system for inducing free radicals by exciting fly ash with microwave ammonium persulfate comprises a dust remover 3, a cooler 4, a fan 9, a flue 2 and a chimney 10, wherein the dust remover 3, the cooler 4, the fan 9 and the chimney 10 are sequentially connected in series through the flue 2; the system comprises a microwave spray reactor 5; the microwave spraying reactor 5 is connected with the cooler 3 and the fan 9 in series through the flue 2, and the microwave spraying reactor 5 comprises a solution spraying reaction area 515, a cooling air inlet 510, a cooling air outlet 511, a flue gas inlet 512, a flue gas outlet 513, a total flue gas inlet 501, a total flue gas outlet 502, a cooling air total inlet 509, a microwave magnetron mounting area 516, a quartz glass partition plate 517, an oxidant supplementing tower 8 and a solution pump 7;
the microwave spraying reactor 5 is formed by connecting a plurality of solution spraying reaction areas 515 in parallel, the solution spraying reaction areas 515 and a microwave magnetron mounting area 516 are sequentially arranged at intervals, and the middle of 2 areas is separated by a quartz glass partition plate 517;
the flue gas inlet 515 and the flue gas outlet 515 are respectively positioned at two sides of the solution spraying reaction area; a plurality of nozzles 503 are arranged in parallel in the middle of the solution spraying reaction area 515;
the nozzle 503 is connected with an oxidant supplementing tower 8 through a solution pump 7, and the oxidant is ammonium persulfate solution; the total flue gas inlet 501 is communicated with each flue gas inlet 512, the total flue gas outlet 502 is communicated with each flue gas outlet 513, and the total flue gas inlet 501 and the total flue gas outlet 502 are respectively communicated with the flue 2.
The cooling air inlet 510 and the cooling air outlet 511 are respectively positioned at two sides of the microwave magnetron mounting region 516; the microwave magnetron mounting area 516 is provided with a plurality of microwave magnetrons 504; the cooling air inlet (510) is respectively communicated with a cooling air main inlet 509 and a cooling air outlet 511.
The bottom of the microwave spraying reactor 5 is provided with an inclined groove 505, and the bottom of the inclined groove 505 is provided with a product outlet 508 and a circulating liquid outlet 507; the product outlet 508 is connected to a mercury separation column 6.
The width b of each solution spraying reaction area 515 of the microwave spraying reactor 5 is between 0.1m and 0.6 m; the total width W of the microwave spraying reactor 5 is between 0.2m and 8 m; the transverse spacing a between the microwave magnetrons 504 is between 0.1m and 0.8 m; the total length L of the microwave spraying reactor 5 is between 0.2m and 8 m; the total height H of the microwave spray reactor 5 lies between 0.2m and 10 m. The nozzles 503 have a lateral arrangement pitch of 2a (a is a lateral pitch between microwave magnetrons) and a longitudinal arrangement pitch of 1.5 a.
The grain diameter of atomized liquid drops sprayed by the nozzle is not more than 80 microns, and the microwave radiation power density in the microwave spraying reactor is 20W/m3-1600W/m3。
Based on the system, the flue gas demercuration method for exciting fly ash induced free radicals by microwave ammonium persulfate is also provided, and the method is operated as follows, firstly, Hg-containing flue gas from a combustor is enabled to be firstly0The flue gas is dedusted and cooled and then enters a microwave spray reactor, and the fly ash is excited by microwaves to activate an ammonium persulfate solution in the microwave spray reactor to generate hydroxyl and sulfate radicals to remove Hg in the flue gas0Oxidizing the mercury into a bivalent mercury solution, and separating and recycling the bivalent mercury solution after the bivalent mercury solution enters a mercury separation tower and is added with bivalent sulfur ions to react to generate mercuric sulfide precipitate.
The optimal concentration of the fly ash in the flue gas is 0.2g/m3-200g/m3(ii) a The temperature in the microwave spraying reactor is controlled to be 25-160 ℃.
The effective liquid-gas ratio of the ammonium persulfate solution to the flue gas is 1-12L/m3The effective concentration of the ammonium persulfate solution is between 0.05 and 2.5mol/L, and the pH value of the solution is between 0.1 and 9.9;
hg in the flue gas0The content of (A) is not more than 1000 mu g/m3(ii) a The combustor is any one of a coal-fired boiler, an industrial kiln way or a garbage incinerator.
The microwave in the microwave spray reactor excites fly ash to activate oxidant ammonium persulfate in the microwave spray reactor to generate hydroxyl and sulfate radical to remove Hg in flue gas0Oxidizing the mercury into a bivalent mercury solution, adding the bivalent mercury solution into a mercury separation tower, reacting by adding bivalent sulfur ions to generate mercuric sulfide precipitate, and separating and recovering the mercuric sulfide precipitate; the system can realize Hg0The removal rate is 100 percent, and the removal process has no secondary pollution and has wide market application prospect.
Example 2:
hg in flue gas0At a concentration of60μg/m3The flue gas temperature is 40 ℃, the molar concentration of ammonium persulfate is 0.1mol/L, the pH of the solution is 3.8, and the fly ash concentration is 6g/m3The microwave radiation power density is 200W/m3The liquid-gas ratio is 2L/m3. The bench test results are: hg in flue gas0The removal efficiency can reach 43.1 percent.
Example 3:
hg in flue gas0The concentration is 60 mug/m3The flue gas temperature is 40 ℃, the molar concentration of ammonium persulfate is 0.2mol/L, the pH of the solution is 3.8, and the fly ash concentration is 6g/m3The microwave radiation power density is 200W/m3The liquid-gas ratio is 2L/m3. The bench test results are: hg in flue gas0The removal efficiency of the catalyst can reach 54.7 percent.
Example 4:
hg in flue gas0The concentration is 60 mug/m3The flue gas temperature is 40 ℃, the molar concentration of ammonium persulfate is 0.2mol/L, the pH of the solution is 3.8, and the fly ash concentration is 6g/m3The microwave radiation power density is 400W/m3The liquid-gas ratio is 2L/m3. The bench test results are: hg in flue gas0The removal efficiency of the catalyst can reach 69.9 percent.
Example 5:
hg in flue gas0The concentration is 60 mug/m3The flue gas temperature is 40 ℃, the molar concentration of ammonium persulfate is 0.2mol/L, the pH of the solution is 3.8, and the fly ash concentration is 6g/m3The microwave radiation power density is 400W/m3The liquid-gas ratio is 3L/m3. The bench test results are: hg in flue gas0The removal efficiency of the catalyst can reach 87.1 percent.
Example 6:
hg in flue gas0The concentration is 60 mug/m3The flue gas temperature is 40 ℃, the molar concentration of ammonium persulfate is 0.3mol/L, the pH of the solution is 3.8, and the fly ash concentration is 6g/m3The microwave radiation power density is 400W/m3The liquid-gas ratio is 3L/m3. The bench test results are: hg in flue gas0The removal efficiency can reach 94.2 percent.
Example 7:
hg in flue gas0The concentration is 60 mug/m3The flue gas temperature is 40 ℃, the molar concentration of ammonium persulfate is 0.4mol/L, the pH of the solution is 3.8, and the fly ash concentration is 6g/m3The microwave radiation power density is 500W/m3The liquid-gas ratio is 3L/m3. The bench test results are: hg in flue gas0The removal efficiency of the catalyst can reach 100 percent.
Example 8:
hg in flue gas0The concentration is 60 mug/m3The flue gas temperature is 90 ℃, the molar concentration of ammonium persulfate is 0.4mol/L, the pH value of the solution is 3.8, and the fly ash concentration is 6g/m3The microwave radiation power density is 500W/m3The liquid-gas ratio is 3L/m3. The bench test results are: hg in flue gas0The removal efficiency of the catalyst can reach 91.2 percent.
The comprehensive comparison of the above examples shows that example 7 has the best removal effect, and the removal efficiency reaches 100%, and can be used as the best example.
Claims (10)
1. A flue gas demercuration system for exciting fly ash induced radicals by microwave ammonium persulfate comprises a dust remover (3), a cooler (4), a fan (9), a flue (2) and a chimney (10), wherein the dust remover (3), the cooler (4), the fan (9) and the chimney (10) are sequentially connected in series through the flue (2); characterized in that the system further comprises a microwave spray reactor (5); the microwave spraying reactor (5) is connected with the cooler (4) and the fan (9) in series through the flue (2), and the microwave spraying reactor (5) comprises a solution spraying reaction area (515), a cooling air inlet (510), a cooling air outlet (511), a flue gas inlet (512), a flue gas outlet (513), a total flue gas inlet (501), a total flue gas outlet (502), a cooling air total inlet (509), a microwave magnetron mounting area (516), a quartz glass partition plate (517), an oxidant supplementing tower (8) and a solution pump (7);
the microwave spraying reactor (5) is formed by connecting a plurality of solution spraying reaction areas (515) in parallel, the solution spraying reaction areas (515) and a microwave magnetron mounting area (516) are sequentially arranged at intervals, and the middle of 2 areas is separated by a quartz glass partition plate (517);
the flue gas inlet (512) and the flue gas outlet (513) are respectively positioned at two sides of the solution spraying reaction zone; a plurality of nozzles (503) are arranged in parallel in the middle of the solution spraying reaction zone (515); the nozzle (503) is connected with an oxidant supplementing tower (8) through a solution pump (7), and the oxidant is ammonium persulfate solution; the total flue gas inlet (501) is communicated with each flue gas inlet (512), the total flue gas outlet (502) is communicated with each flue gas outlet (513), and the total flue gas inlet (501) and the total flue gas outlet (502) are respectively communicated with the flue (2);
the cooling air inlet (510) and the cooling air outlet (511) are respectively positioned at two sides of the microwave magnetron mounting region (516); the microwave magnetron mounting area (516) is provided with a plurality of microwave magnetrons (504); the cooling air inlet (510) is respectively communicated with a cooling air main inlet (509) and a cooling air outlet (511);
the microwave radiation power density in the microwave spray reactor (5) is 20W/m3- 1600 W/m3。
2. The system according to claim 1, characterized in that the bottom of the microwave spray reactor (5) is provided with an inclined groove (505), and the bottom of the inclined groove (505) is provided with a product outlet (508) and a circulating liquid outlet (507); the product outlet (508) is connected with a mercury separation tower (6); the oxidant is ammonium persulfate solution.
3. The system according to claim 1, characterized in that the total width W of the microwave spray reactor (5) is comprised between 0.2m and 8 m; the total length L of the microwave spraying reactor (5) is between 0.2m and 8 m; the total height H of the microwave spray reactor (5) is between 0.2m and 10 m.
4. The system of claim 1, wherein the solution spray reaction zone (515) has a width b between 0.1m and 0.6 m.
5. The system of claim 1, wherein the lateral spacing a between the microwave magnetrons (504) is between 0.1m-0.8 m; the nozzles (503) are arranged at a transverse pitch of 2a and a longitudinal pitch of 1.5 a.
6. The system of claim 1, wherein the nozzle (503) emits atomized droplets having a particle size of no greater than 80 microns.
7. A flue gas demercuration method by exciting fly ash induced free radicals with microwave ammonium persulfate, which is characterized in that the method is completed based on the system of claim 1, and firstly, Hg-containing flue gas from a combustor is enabled to be discharged0The flue gas is dedusted and cooled and then enters a microwave spray reactor, and the fly ash is excited by microwaves to activate an ammonium persulfate solution in the microwave spray reactor to generate hydroxyl and sulfate radicals to remove Hg in the flue gas0Oxidizing the mercury into a bivalent mercury solution, and separating and recycling the bivalent mercury solution after the bivalent mercury solution enters a mercury separation tower and is added with bivalent sulfur ions to react to generate mercuric sulfide precipitate.
8. The method of claim 7, wherein the optimum concentration of fly ash in the flue gas is 0.2g/m3-200g/m3(ii) a The temperature in the microwave spraying reactor is controlled to be 25-160 ℃.
9. The method of claim 7, wherein the effective liquid-to-gas ratio of ammonium persulfate solution to flue gas is from 1 to 12L/m3The effective concentration of the ammonium persulfate solution is between 0.05 and 2.5mol/L, and the pH value of the solution is between 0.1 and 9.9.
10. The method of claim 7, wherein Hg in the flue gas0The content of (a) is not higher than 1000 mug/m3(ii) a The combustor is any one of a coal-fired boiler, an industrial kiln or a waste incinerator.
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| CN104785076A (en) * | 2015-04-21 | 2015-07-22 | 南京朗洁环保科技有限公司 | Method for simultaneous desulfurization denitrification and mercury removal based on hydroxyl and sulphate radical oxidation |
| CN105565465A (en) * | 2015-12-15 | 2016-05-11 | 广东工业大学 | Method for treating phthalate wastewater by means of catalyzing persulfate by utilization of supported activated carbon in microwave inducement manner |
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| CN104785076A (en) * | 2015-04-21 | 2015-07-22 | 南京朗洁环保科技有限公司 | Method for simultaneous desulfurization denitrification and mercury removal based on hydroxyl and sulphate radical oxidation |
| CN105565465A (en) * | 2015-12-15 | 2016-05-11 | 广东工业大学 | Method for treating phthalate wastewater by means of catalyzing persulfate by utilization of supported activated carbon in microwave inducement manner |
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