CN201618514U - Simultaneous removal of multiple pollutants by electrocatalytic oxidation combined with lime-gypsum method - Google Patents

Abstract

The utility model discloses a device for simultaneously removing various pollutants by electrocatalytic oxidation combined with lime-gypsum method. The device includes a spray cooling device, an electrostatically enhanced reactor, a Venturi device, a double-cycle multi-pollutant integrated absorption tower, and a wet electrostatic demister. The flue gas enters the electrostatically enhanced reactor after being cooled by the spray cooling device. The corona discharge treatment is carried out in the corona discharge area formed in the enhanced reactor, and the treated flue gas enters the double-cycle multi-pollutant integrated absorption tower, and the dust removal and spray absorption in the absorption tower are purified. The final flue gas enters the corrugated plate demister and electrostatic demister on the upper part of the spray tower in turn to remove the aerosol in the flue gas. The utility model has the following advantages: 1) realize simultaneous removal of multiple pollutants, and effectively control the pollution of fine particles and aerosols; 2) higher removal efficiency for various pollutants; 3) removal and absorption The by-products will not cause secondary pollution to the environment.

Description

Simultaneous removal of multiple pollutants by electrocatalytic oxidation combined with lime-gypsum method

technical field

The utility model belongs to the technical field of environmental protection, in particular to a device for simultaneously removing various pollutants by electrocatalytic oxidation combined with lime-gypsum method.

Background technique

At present, different equipment and methods are generally used to control pollutants such as sulfur oxides, nitrogen oxides, polycyclic aromatic hydrocarbons and dioxins in coal-fired flue gas at home and abroad. The main control technologies of sulfur oxides at home and abroad are limestone-gypsum desulfurization technology and semi-dry desulfurization technology. Among them, the limestone-gypsum desulfurization technology has disadvantages such as large investment, high operating costs, and difficult recycling of desulfurization by-products; while the semi-dry desulfurization technology generally has poor adaptability to high-sulfur coal, and is mainly used in units below 300MW. Power plant and combined heat and power boiler tail gas desulfurization.

The main technologies for removing nitrogen oxides in flue gas at home and abroad are selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR). However, both SCR and SNCR need to install expensive and complicated equipment to remove nitrogen oxides. For example, in the installation of SCR equipment, the cost of its catalyst accounts for 35% of the total investment, and the general equipment needs to be replaced with a new catalyst after 2 to 3 years of operation, and the operating cost is very high. These two processes are less used in developing countries.

At home and abroad, the treatment of metallic mercury, polycyclic aromatic hydrocarbons and dioxins is in its infancy, and there is no mature process technology, and most of them are removed by activated carbon adsorption. The product after activated carbon adsorption is hazardous solid waste, which may cause secondary pollution. In addition, the disposal cost of such hazardous solid waste is also quite expensive.

So far, there is no technology that can simultaneously remove the four pollutants of sulfur oxides, nitrogen oxides, polycyclic aromatic hydrocarbons and dioxins in flue gas. After entering the 1990s, people began to gradually realize that the separate treatment of various pollutants not only occupies a large area, but also requires high investment costs. In order to reduce the cost of flue gas purification and meet the needs of existing power plants, it has become the development trend of flue gas purification technology to develop new technologies and new equipment that can simultaneously remove multiple pollutants.

A flue gas purification technology using electrocatalytic oxidation combined with lime-gypsum absorption can simultaneously remove sulfur oxides, nitrogen oxides, metallic mercury, polycyclic aromatic hydrocarbons and dioxins in flue gas. The principle is to use non-pollutants such as water vapor and oxygen in the flue gas as the source of free radicals, and under the action of the corona area, they are decomposed into oxidative free radicals such as O, OH, O ₃ , HO ₂ , etc. SO ₂ , NOx, Hg ⁰ , polycyclic aromatic hydrocarbons and dioxins in the gas react to produce SO ₃ , H ₂ SO ₄ , NO ₂ , HNO ₃ , divalent mercury, CO ₂ and H ₂ O, and these reaction products are It is absorbed in the lime-gypsum process, so as to realize the simultaneous removal of various pollutants.

Contents of the invention

The purpose of this utility model is to provide an electrocatalytic oxidation combined lime-gypsum for the current technical blank that can simultaneously remove sulfur oxides, nitrogen oxides, metal mercury, polycyclic aromatic hydrocarbons and dioxins in flue gas. Simultaneous removal of multiple pollutants in the method.

The simultaneous removal of multiple pollutants by electrocatalytic oxidation combined with lime-gypsum method includes booster fan, spray cooling device, electrostatically enhanced reactor, Venturi device, double-cycle multi-pollutant integrated absorption tower, wet electrostatic demisting Process water tank, process water pump, lime slurry tank, lime slurry pump, lime slurry circulation box, lime slurry circulation pump, sedimentation tank, gray water circulation pump, oxidation fan, process water is transported from the process water tank to the spray cooling system through the process water pump device, lime slurry tank, wet electrostatic demister, and double-cycle multi-pollutant integrated absorption tower upper layer demister; the flue gas enters the spray cooling device through the booster fan, sprays the process water to cool down, and passes through the electrostatic enhancement reactor Corona discharge treatment, in which the air is transported by the oxidation fan, and then enters the double-cycle multi-pollutant integrated absorption tower through the Venturi device, and the flue gas in the double-cycle multi-pollutant integrated absorption tower is sprayed and dedusted by the gray water circulation pump After spraying and absorbing treatment, the flue gas enters the wet electrostatic demister and is discharged from the chimney; the gray water after spraying and the process water passed through the spray cooling device all enter the sedimentation tank; the lime slurry flows from the lime slurry tank through the lime slurry pump Enter the lime slurry circulation box, and then enter the dual-cycle multi-pollutant integrated absorption tower through the lime slurry circulation pump to spray and absorb the flue gas.

The electrostatically enhanced reactor is a rectangular structure, including an insulation device, an upper air chamber, a nozzle electrode, a corona discharge area, an electrode plate, a gas mixing chamber, an oxidation fan interface, an air distribution plate, and a lower air chamber. There are an upper air chamber, a corona discharge area, a mixed air chamber, and a lower air chamber. The corona discharge area is divided into multiple corona discharge units, and each corona discharge unit is separated by an electrode plate. The nozzle electrodes are arranged side by side in the discharge unit, and the nozzle electrodes are placed perpendicular to the pole plate. There is an air distribution plate between the gas mixing chamber and the lower gas chamber. The electrostatic enhancement reactor shell in the gas mixing chamber area is equipped with an oxidation fan interface. The top of the reinforced reactor is provided with an insulating device.

The double-cycle multi-pollutant integrated absorption tower includes the absorption tower inlet, gray water storage tank, gray water spray layer, lime slurry storage tank, lime slurry spray layer, corrugated plate demister, and double-cycle multi-pollutant integrated The chemical absorption tower adopts a two-stage design. The lower part of the double-cycle multi-pollutant integrated absorption tower is the gray water storage tank and the gray water spray layer, and the upper part is the lime slurry storage tank and the lime slurry spray layer, and the lime slurry spray layer It has a spray structure of 2 to 4 layers. The top of the double-cycle multi-pollutant integrated absorption tower is a corrugated plate demister. The flue gas enters the double-cycle multi-pollutant integrated absorption tower from the entrance of the absorption tower. The spray layer and Venturi device are combined with spray dedusting, and then enter the lime slurry spray layer to desulfurize and denitrify through the lime slurry empty tower spray, and then go through the corrugated plate demister to remove the fog and then discharge the dual-cycle multi-pollutant integrated absorption tower.

Compared with the prior art, the utility model has the beneficial effects:

1) It can realize the simultaneous removal of various pollutants, such as sulfur oxides, nitrogen oxides, polycyclic aromatic hydrocarbons and dioxins, which greatly saves investment costs for flue gas treatment, and the process is simple and reliable;

2) The removal efficiency of pollutants is high, among which the removal efficiency of sulfur oxides can reach more than 95%, the removal efficiency of nitrogen oxides can reach more than 60%, and the removal efficiency of metal mercury can reach more than 80%. The removal efficiency of aromatic hydrocarbons and dioxins can reach more than 80%;

3) The removal of by-products by the device will not cause secondary pollution to the environment;

4) The device can effectively control fine particle (PM _2.5 ) and aerosol pollution.

Description of drawings

Figure 1 Schematic diagram of the structure of the simultaneous removal of multiple pollutants by electrocatalytic oxidation combined with lime-gypsum method;

Fig. 2 is the structural representation of the electrostatically enhanced reactor of the utility model;

Fig. 3 is a structural schematic diagram of the double-cycle multi-pollutant integrated absorption tower of the present utility model;

In the figure: booster fan 1, spray cooling device 2, electrostatic enhanced reactor 3, Venturi device 4, double-cycle multi-pollutant integrated absorption tower 5, wet electrostatic demister 6, process water tank 7, process water pump 8. Lime slurry tank 9. Lime slurry pump 10. Lime slurry circulation box 11. Lime slurry circulation pump 12. Sedimentation tank 13. Gray water circulation pump 14. Oxidation fan 15. Insulation device 16. Upper air chamber 17. Nozzle electrode 18. Corona discharge area 19, partition 20, gas mixing chamber 21, oxidation fan interface 22, air distribution plate 23, lower air chamber 24, absorption tower inlet 25, gray water storage tank 26, gray water spray layer 27, lime slurry Storage tank 28, lime slurry spray layer 29, corrugated plate demister 30.

Detailed ways

As shown in Figure 1, the simultaneous removal of multiple pollutants in the electrocatalytic oxidation combined lime-gypsum process includes a booster fan 1, a spray cooling device 2, an electrostatically enhanced reactor 3, a Venturi device 4, and a double-cycle multiple pollution Material integrated absorption tower 5, wet electrostatic demister 6, process water tank 7, process water pump 8, lime slurry tank 9, lime slurry pump 10, lime slurry circulation box 11, lime slurry circulation pump 12, sedimentation tank 13, ash Water circulation pump 14, oxidation blower 15, process water is transported from process water tank 7 through process water pump 8 to spray cooling device 2, lime slurry tank 9, wet electrostatic demister 6 and the upper layer of double-cycle multi-pollutant integrated absorption tower 5 Demister; the flue gas enters the spray cooling device 2 through the booster fan 1, and after being sprayed and cooled by process water, it is treated by the corona discharge of the electrostatic enhancement reactor 3, in which the air is transported by the oxidation fan 15, and then passes through the Venturi device 4 Enter the double-cycle multi-pollutant integrated absorption tower 5, after the flue gas in the double-cycle multi-pollutant integrated absorption tower 5 is sprayed and dusted by the gray water circulation pump 14 and sprayed and absorbed, the flue gas enters the wet electrostatic demister 6. Finally, it is discharged from the chimney; the gray water after spraying and the process water passed through the spray cooling device 2 all enter the sedimentation tank 13; the lime slurry enters the lime slurry circulation box 11 from the lime slurry tank 9 through the lime slurry pump 10, and then passes through the lime slurry tank 9. The slurry circulation pump 12 enters the dual-cycle multi-pollutant integrated absorption tower 5 to spray and absorb the flue gas.

As shown in Figure 2, the electrostatic enhancement reactor 3 is a rectangular structure, including an insulating device 16, an upper gas chamber 17, a nozzle electrode 18, a corona discharge area 19, a pole plate 20, a gas mixing chamber 21, an oxidation fan interface 22, cloth Wind plate 23, lower air chamber 24, the electrostatic enhancement reactor 3 is provided with an upper air chamber 17, a corona discharge area 19, a gas mixing chamber 21, and a lower air chamber 24 from top to bottom, and the corona discharge area 19 is divided into multiple Corona discharge unit, each corona discharge unit is separated by pole plate 20, nozzle electrodes 18 are arranged side by side in each corona discharge unit, nozzle electrodes 18 are placed perpendicular to pole plate 20, gas mixing chamber 21 and lower gas chamber An air distribution plate 23 is provided between 24, an oxidation fan interface 22 is provided on the shell of the electrostatically enhanced reactor 3 in the area of the gas mixing chamber 21, and an insulating device 16 is provided on the top of the electrostatically enhanced reactor 3. The electrostatically enhanced reactor adopts the patented free radical shower technology, which generates strong oxidizing free radicals through positive corona, and oxidizes NO in the flue gas into easily absorbed NO2, HNO3 and HNO2 and other substances.

As shown in Figure 3, the dual-cycle multi-pollutant integrated absorption tower 5 includes an absorption tower inlet 25, a gray water storage tank 26, a gray water spray layer 27, a lime slurry storage tank 28, a lime slurry spray layer 29, corrugated The plate demister 30 and the double-cycle multi-pollutant integrated absorption tower 5 adopt a two-stage design, and dust removal, desulfurization and denitrification are implemented in stages. The lower part of the double-cycle multi-pollutant integrated absorption tower 5 is the gray water storage tank 26 and the gray water spray layer 27, which is combined with the Venturi device 4 to perform spray dust removal to achieve the dust removal effect, and the upper part is the lime slurry storage tank 28 and lime slurry The spray layer 29, the lime slurry spray layer 29 has a 2-4 layer spray structure, and the lime slurry is used to spray desulfurization and denitrification in an empty tower to realize the function of desulfurization and denitrification. The top of the double-cycle multi-pollutant integrated absorption tower 5 is a corrugated plate demister 30, and the flue gas enters the double-cycle multi-pollutant integrated absorption tower 5 from the absorption tower inlet 25, and first passes through the gray water spray layer 27 and the venturi. The device 4 is combined with spray dedusting, and then enters the lime slurry spray layer 29, desulfurizes and denitrates through the lime slurry empty tower spray, and then discharges the double-cycle multi-pollutant integrated absorption tower 5 after demisting by the corrugated plate demister 30. The water circulation separation in the upper and lower parts of the double-cycle multi-pollutant integrated absorption tower can solve the problem of blockage of the internal equipment of the absorption tower.

The simultaneous removal of multiple pollutants by electrocatalytic oxidation combined with lime-gypsum method is as follows: the flue gas enters the spray cooling device 2, the temperature of the flue gas is adjusted to 70-80°C, and the flue gas enters the bottom of the electrostatically enhanced reactor 3 into the lower Air chamber 24, the flue gas will have a buffer in the lower air chamber 24, there is an air distribution plate 23 on the upper part of the lower air chamber 24, and the upper part of the air distribution plate 23 is the air mixing chamber 21, and the supplementary oxidized air will be in the air mixing chamber 21 Add and mix evenly with the flue gas. The upper part of the gas mixing chamber 21 is a corona discharge area 19. The corona discharge area 19 is divided into multiple corona discharge units according to the amount of flue gas treatment. Each corona discharge unit is composed of a plate 20 Separated, the distance between the pole plates 20 is 80-120mm, and multiple nozzle electrodes 18 are arranged side by side in each corona discharge unit. The number of nozzle electrodes 18 can be adjusted according to the actual smoke volume. The corona discharge reactor uses 20kV ~ 50kV DC high voltage, the nozzle electrode 18 is connected to positive high voltage, and the pole plate is connected to negative high voltage. The wet flue gas is decomposed into strong oxidizing free radicals (such as O, OH, O ₃ , HO _{2 ,} etc.) in the electrostatic enhancement reactor 3 . These free radical substances can effectively oxidize SO ₂ in flue gas to SO ₃ and H ₂ SO ₄ , etc., oxidize NOx to NO ₂ and HNO ₃ , etc., oxidize Hg ⁰ to divalent mercury, and degrade polycyclic aromatic hydrocarbons and dioxins to Harmless substances (such as CO ₂ , H ₂ O, etc.). The upper part of the corona discharge area 19 is the upper air chamber 17 and the flue gas outlet. The flue gas buffered by the upper air chamber 17 flows out from the outlet and enters the double-cycle multi-pollutant integrated absorption tower 5, and the double-cycle multi-pollutant integration The lower part of the absorption tower 5 is the gray water storage tank 26 and the gray water spray layer 27. The gray water is continuously transported to the gray water spray layer 27 by the sedimentation tank 13 under the action of the gray water circulation pump 14, and is combined with the Venturi device 4 to counteract the smoke. 2 to 4 lime slurry spray layers 29 and lime slurry storage tanks 28 are installed on the upper part of the double-cycle multi-pollutant integrated absorption tower 5, which are continuously transported to the lime slurry spray by the lime slurry circulation pump 12 Layer 29 fully contacts and reacts with the countercurrent flue gas, and sprays the flue gas to absorb and remove various pollutants in the flue gas. The spray liquid-gas ratio is 8-20, and the flue gas emission at the system outlet is less than 30 mg/m ³ ; SO ₂ emission is less than 200mg/m ³ , and the desulfurization efficiency of the system is not less than 96%; NO emission concentration is less than 150mg/m ³ , and the system denitrification efficiency is not less than 60%, and the double-cycle multi-pollutant integrated absorption tower 5 up and down Slurry cycle separation at the bottom of the absorption tower can solve the problem of blockage of the equipment inside the absorption tower; the purified flue gas enters the corrugated plate demister 30 on the upper part of the double-cycle multi-pollutant integrated absorption tower 5, and is demistered by the corrugated plate demister 30 The amount of aerosol in the fogged flue gas is less than 100mg/m3, and the flue gas passes through the wet electrostatic demister 6. The wet electrostatic demister 6 can efficiently capture the acid mist and uncaptured smoke from the absorption tower. Solve the corrosion problem at the tail of the wet absorption tower and further improve the dust removal effect. After further demisting by the wet electrostatic demister, the aerosol amount is less than 30mg/m3, and then discharged through the chimney.

Claims (3)

1. the multiple pollutant of a catalytic oxidation associating lime-gypsum method removes device simultaneously, it is characterized in that comprising booster fan (1), mist cooling device (2), static enhancing reactor (3), Venturi (4), the integrated absorption tower of the multiple pollutant of two circulations (5), wet electrostatic demister (6), technology water pot (7), technology water pump (8), lime slurry case (9), lime white liquid pump (10), lime slurry circulating box (11), lime slurry circulating pump (12), sedimentation basin (13), ash water-circulating pump (14), oxidation fan (15), fresh water (FW) is delivered to mist cooling device (2) by technology water pot (7) through technology water pump (8), lime slurry case (9), wet electrostatic demister (6) and upper strata, the integrated absorption tower of the multiple pollutant of two circulation (5) demister; Flue gas enters mist cooling device (2) behind the fresh water (FW) spraying cooling through booster fan (1), Corona discharge Treatment through static enhancing reactor (3), wherein air is carried by oxidation fan (15), after Venturi (4) enters two circulations integrated absorption tower of multiple pollutant (5), flue gas is after grey water-circulating pump (14) spray for dust suppression and spray absorption processing in the integrated absorption tower of the multiple pollutant of two circulations (5), flue gas enters wet electrostatic demister (6), and the back is discharged by chimney; Buck behind the spray and all enter sedimentation basin (13) through the fresh water (FW) of mist cooling device (2); Lime slurry enters lime slurry circulating box (11) by lime slurry case (9) through lime white liquid pump (10), after lime slurry circulating pump (12) enters two circulation integrated absorption towers of multiple pollutant (5) flue gas is sprayed the absorption processing.

2. the multiple pollutant of a kind of catalytic oxidation associating lime-gypsum method according to claim 1 removes device simultaneously, it is characterized in that described static enhancing reactor (3) is a rectangle structure, comprise seal (16), upper chamber (17), injector electrode (18), corona discharging area (19), pole plate (20), mixing chamber (21), oxidation fan interface (22), air distribution plate (23), lower chamber (24), be provided with upper chamber (17) in the static enhancing reactor (3) from top to bottom, corona discharging area (19), mixing chamber (21), lower chamber (24), corona discharging area (19) is divided into a plurality of corona discharges unit, each corona discharge unit is separated by pole plate (20), injector electrode (18) is arranged side by side in each corona discharge unit, injector electrode (18) is placed perpendicular to pole plate (20), be provided with air distribution plate (23) between mixing chamber (21) and the lower chamber (24), static enhancing reactor (3) housing in mixing chamber (21) zone is provided with oxidation fan interface (22), and static enhancing reactor (3) top is provided with seal (16).

3. the multiple pollutant of a kind of catalytic oxidation associating lime-gypsum method according to claim 1 removes device simultaneously, it is characterized in that described two circulation integrated absorption towers of multiple pollutant (5) comprise absorption tower inlet (25), buck storage tank (26), buck spraying layer (27), lime slurry storage tank (28), lime slurry spraying layer (29), corrugated plating demister (30), two-piece design is adopted on the integrated absorption tower of the multiple pollutant of two circulations (5), bottom, the integrated absorption tower of the multiple pollutant of two circulations (5) is buck storage tank (26) and buck spraying layer (27), top is lime slurry storage tank (28) and lime slurry spraying layer (29), lime slurry spraying layer (29) is 2～4 layers of spray structure, top, the integrated absorption tower of the multiple pollutant of two circulations (5) is corrugated plating demister (30), flue gas enters two circulations integrated absorption tower of multiple pollutant (5) by absorption tower inlet (25), earlier combine spray for dust suppression with Venturi (4) through buck spraying layer (27), after enter lime slurry spraying layer (29) through lime slurry hollow-spraying-tower desulphurization denitration, after discharge two circulations integrated absorption towers of multiple pollutant (5) after corrugated plating demister (30) demist.

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