CN104984656B - Multistage internal circulation semi-dry method desulfurization, denitrification and demercuration integrated device - Google Patents

Abstract

A multi-stage internal circulation semi-dry desulfurization, denitration and demercuration integrated device belongs to the field of flue gas purification. The invention can jointly remove sulfur, nitrate and mercury in flue gas. The lower part of the first-stage internal circulation reactor is a large Venturi tube, and a small Venturi tube is installed inside the large Venturi tube. The large Venturi tube is connected with the ash hopper, and the ash hopper is connected with the flue gas inlet, and ClO ₂ is installed in the flue gas inlet. Distributor, each stage of internal circulation reactor is equipped with dual lye atomizing nozzles, and the dual lye atomizing nozzles are connected to the container containing dual lye through the slurry pump, and the top of each stage of internal circulation reactor is fixed with a U Slot separator, the Nth-stage internal circulation reactor is connected to the flue gas outlet, the flue gas outlet is connected to the bag filter, the bag filter is connected to the induced draft fan, and the bag filter is connected to the ash storage tank and ash bin through the ash discharge pipeline. Connected, the lower port of the ash storage tank is provided with a screw feeder, and the ash discharge port of the screw feeder is connected with the small Venturi tube through the feeding pipe. The invention is used for removing sulfur, nitrate and mercury in flue gas.

Description

Multi-stage internal circulation semi-dry desulfurization, denitrification and mercury removal integrated device

technical field

The invention relates to a multi-stage internal circulation semi-dry desulfurization, denitrification and mercury removal device. The invention belongs to the field of flue gas purification.

Background technique

Coal is the main energy source in our country. Heavy metal pollutants such as S0 ₂ , N0 _x and Hg produced by coal combustion seriously pollute the atmosphere. Among them, S0 ₂ and NOx are the main sources of pollution such as acid rain and photochemical smog. The organisms are easy to deposit and have strong hysteresis, which seriously damages human health. Therefore, it is urgent to control the emission of S0 ₂ , NOx and Hg in the flue gas from the source.

There are many flue gas treatment technologies, among which the more mature and representative desulfurization technologies include wet method, semi-dry method and dry method, etc., low-temperature denitrification technologies include catalytic reduction method and oxidation method, etc., and mercury removal technologies include wet method and dry method. law etc.

At present, the flue gas desulfurization and denitrification technologies researched and developed in the world can be divided into two categories: one is the series combined staged removal technology, combined with the traditional flue gas desulfurization technology (FGD), selective catalytic reduction technology (SCR) and cloth bag Dust collectors (mercury removal) can independently remove S0 ₂ , NOx and Hg in the flue gas, but this method has complex equipment, large floor space, high process operation requirements, and high purification costs. The removal effect varies greatly depending on the fuel coal quality and flue gas conditions, and the large amount of active coke is easy to cause secondary pollution. The other is to apply a technology to simultaneously remove S0 ₂ , NOx and Hg in the whole system, that is, the integrated technology of desulfurization, denitrification and demercuration. This method desulfurizes, denitrates, and removes mercury in one system at the same time, with obvious advantages, reduced system complexity, better operating performance, convenient management, small footprint, less investment, and low cost, so it is the future air pollution control and important direction of sustainable development.

Chinese invention patent 201320471845.X reports an industrial boiler flue gas combined desulfurization, denitrification and mercury removal device, which uses ozone (0 ₃ ) and calcium-based absorbents as consumption agents, and a circulating fluidized bed as the basic system. Industrial boiler flue gas combined desulfurization, denitrification and mercury removal device for joint removal of various pollutants such as sulfur dioxide (SO ₂ ), nitrogen oxides (NO _X ) and mercury (Hg) in boiler flue gas, which includes ozone generator, Circulating fluidized bed absorber, calcium-based absorbent storage tank, cyclone separator, bag filter and chimney. This device can effectively desulfurize, denitrify and demercurate, but its disadvantages are complex structure, high resistance of the cyclone separator, and huge power consumption of the ozone generator, which is difficult to implement (for example, the amount of flue gas produced by a 20t/h boiler needs to be equipped with an ozone generator with a power of 110KW devices, huge power consumption, poor economy), large floor area, high construction costs, and high operating costs.

Therefore, in order to solve the above technical problems, it is necessary to provide a combined flue gas desulfurization, denitrification and demercuration device with an improved structure to overcome the defects in the prior art.

Contents of the invention

The object of the present invention is to provide a multi-stage internal circulation semi-dry desulfurization, denitrification and mercury removal integrated device which can jointly remove sulfur, nitrate and mercury in flue gas.

The device of the present invention uses double lye (Ca(OH) ₂ , NaOH) as an absorbent, chlorine dioxide (ClO ₂ ) produced by a ClO ₂ generator as a strong oxidant, and an internal circulation reactor as a basic system to treat flue gas Combined removal of various pollutants such as sulfur dioxide (SO ₂ ), nitrogen oxides (NO _x ) and mercury (Hg) in the air. A flue gas inlet is set on one side of the bottom of the device, and a flue gas outlet is set on the top side of the device, so that the flue gas passes through the multi-stage internal circulation reactor from bottom to top.

Realize above-mentioned purpose, technical scheme of the present invention is:

Multi-stage internal circulation semi-dry desulfurization, denitrification and mercury removal integrated device, including flue gas inlet, small venturi tube, multi-stage internal circulation reactor, flue gas outlet, multiple double lye atomizing nozzles, ash hopper, ClO ₂ Distributor, slurry pump, container filled with double lye, multiple U-shaped tank separators, bag filter, induced draft fan, ash storage tank, screw feeder, feeding pipe and ash bin;

The multi-stage internal circulation reactor is vertically arranged, and the multi-stage internal circulation reactor is from the bottom to the top in turn from the first-stage internal circulation reactor to the Nth-stage internal circulation reactor, N is a natural number, and N=3~ 5. The lower part of the first-stage internal circulation reactor is a large venturi tube, and the large venturi tube is composed of a constriction section, a throat pipe and a diffusion section from bottom to top. A small Venturi tube is installed vertically between the throat and the diffusion section in the large Venturi tube. The lower port of the large Venturi tube communicates with the upper port of the ash hopper, and the lower port of the ash hopper is the ash discharge port. , the side wall of the ash hopper communicates with the _flue gas inlet, and a _{ClO2 distributor} is installed in the _flue gas inlet. A horizontal guide plate is arranged at the inlet section of the large Venturi tube, and a vertical guide plate is arranged at the lower part of the constriction section of the large Venturi tube; a rectifying grid is arranged at the throat inlet section of the large Venturi tube; The lower part of the circulation reactor is equipped with a double alkali atomization nozzle, and the double alkali atomization nozzle arranged in the first-stage internal circulation reactor is located in the diffusion section of the large Venturi tube, and all the double alkali The atomizing nozzles are all located on the center line of the multi-stage internal circulation device and set upwards. The inlets of all the dual-alkali atomizing nozzles are connected with the outlets of the slurry pumps. The container is connected, and the top of each internal circulation reactor is fixed with a U-shaped groove separator. The upper port of the Nth internal circulation reactor is connected with the flue gas outlet, and the flue gas outlet is connected to the cloth bag through the pipeline. The inlet of the dust collector is connected, the outlet of the bag filter is connected with the inlet of the induced draft fan through the pipeline, and the ash discharge port at the lower end of the bag filter is respectively connected with the upper port of the ash storage tank and the ash bin through the ash discharge pipeline. , The lower port of the ash storage tank is provided with a screw feeder, and the ash discharge port of the screw feeder communicates with the throat of the small Venturi tube through the feeding pipe.

The beneficial effect of the present invention relative to prior art is:

1. The structure is simple and the reaction efficiency is high. The multi-stage internal circulation reactor is used to fully react and contact the absorbent with the flue gas. Ca(OH) ₂ +NaOH double lye and strong oxidant ClO ₂ are used to effectively desulfurize, denitrify, and desulfurize. Mercury, the desulfurization efficiency reaches 90%, the denitrification and mercury removal efficiency reaches more than 80%, the removal efficiency is high, and the floor area is effectively reduced, and the operating cost is reduced.

2. The present invention realizes the combined removal of various pollutants such as sulfur dioxide (SO ₂ ), nitrogen oxides (NO _X ) and mercury (Hg) in the flue gas, and utilizes the joint action of double lye and ClO ₂ to realize simultaneous Desulfurization, denitrification and mercury removal have improved the effect of air pollution control and met the latest environmental protection emission requirements.

3. Using multi-stage internal circulation reactor, the system resistance is small (resistance is less than or equal to 1500Pa), saving electricity.

4. The combination of horizontal guide plate, vertical guide plate and rectification grid can effectively solve the problem of bias current that has not been solved in the prior art.

5. The present invention adopts dual lye multi-stage injection, which solves the problem of overhumidity of flue gas caused by single-stage injection; makes each stage of internal circulation reactor relatively independent, and has new lye to participate in desulfurization and denitrification, and the overall desulfurization and denitrification efficiency high;

6. From the second stage, the bottom throat (ie, the lower port) of each internal circulation reactor has a high velocity (10~12m/s), a middle velocity of 4~5m/s, and the top is separated by a vertical U-shaped groove This structural design makes a large amount of materials in the internal circulation reactor of each stage circulate strongly, which not only improves the efficiency of desulfurization and denitrification, but also solves the problem of fouling in the internal circulation reactor of each stage.

7. The bag dust collector has a unique structure for collecting ash and recycling. The circulating ash enters the multi-stage internal circulation reactor from a small venturi tube, and the returned ash is evenly distributed in the multi-stage internal circulation reactor, which solves the problem of entering from the rear wall of the reactor in the prior art. , resulting in the unevenness of the return material along the height direction of the reactor, which affects the desulfurization effect.

Description of drawings

Fig. 1 is the overall structure front view of the present invention;

Fig. 2 is a K-K sectional view among Fig. 1;

Fig. 3 is the M-M sectional view among Fig. 1;

Fig. 4 is a partial enlarged view of A place in Fig. 1;

FIG. 5 is a partial enlarged view of B in FIG. 1 .

Fig. 6 is a main sectional view of a conical shell;

Figure 7 is a top view of Figure 6;

FIG. 8 is a partial enlarged view of C in FIG. 6 .

In the figure: flue gas inlet 1, small venturi tube 2, multi-stage internal circulation reactor 3, flue gas outlet 4, double lye atomizing nozzle 5, ash hopper 6, ClO ₂ distributor 7, slurry pump 8, dresser Container with double lye 9, U-shaped tank separator 10, bag filter 11, induced draft fan 12, ash storage tank 13, screw feeder 14, feeding pipe 15, ash bin 16, large venturi pipe 17, Ash outlet 18, chimney 19, conical shell 20, ventilation hole 21, ring outer edge 22, U-shaped trough 23, horizontal guide plate 24, vertical guide plate 25, flue gas guide plate 26, rectifying grille 27 , grid plate 28 and ClO ₂ generator 29.

detailed description

Specific implementation mode 1: As shown in Figures 1 to 8, a multi-stage internal circulation semi-dry desulfurization, denitrification and mercury removal integrated device includes a flue gas inlet 1, a small venturi tube 2, a multi-stage internal circulation reactor 3, and a flue gas inlet. Gas outlet 4, multiple double lye atomizing nozzles 5, ash hopper 6, ClO2 distributor ₇ , slurry pump 8, container filled with double lye 9, multiple U-shaped groove separators 10, bag filter 11 , induced draft fan 12, ash storage tank 13, screw feeder 14, feeding pipe 15 and ash bin 16;

The multi-stage internal circulation reactor 3 is vertically arranged, and the multi-stage internal circulation reactor 3 is sequentially from the first-stage internal circulation reactor to the Nth-stage internal circulation reactor from bottom to top, N is a natural number, and N= 3~5; the lower part of the first-stage internal circulation reactor is a large venturi tube 17, and the large venturi tube 17 is composed of a constriction section, a throat pipe and a diffusion section from bottom to top. In the large Venturi tube 17, a small Venturi tube 2 is vertically arranged between the throat pipe and the diffusion section (the structural shape of the small Venturi tube 2 is similar to that of the large Venturi tube 17), and the large Venturi tube 17 The lower port is connected with the upper port of the ash hopper 6, the lower port of the ash hopper 6 is the ash discharge port 18, and the side wall of the ash hopper 6 is connected with the flue gas inlet 1 (the flue gas inlet 1 is connected with the boiler exhaust duct Through), the flue gas inlet ₁ is equipped with a ClO2 distributor ₇ , the several ClO2 nozzles of the ClO2 distributor ₇ spray in the same direction as the flue gas flow, and the large Venturi tube 17 after the ClO2 distributor ₇ A horizontal guide plate 24 is arranged at the entrance section, and a vertical guide plate 25 is arranged at the lower part of the contraction section of the large Venturi tube 17 (the vertical guide plate 25 matches the horizontal guide plate 24); Grille 27; the lower part of each stage of the multi-stage internal circulation reactor 3 is provided with a double lye atomizing nozzle 5, and the double lye mist arranged in the first stage internal circulation reactor The atomization nozzle 5 is located in the diffusion section of the large venturi tube 17 (to strengthen the mixing of the smoke and the droplets as soon as possible), and all the double lye atomization nozzles 5 are located on the center line of the multi-stage internal circulation device 3 and set upwards , the inlets of all double lye atomizing nozzles 5 are all connected with the outlet of the slurry pump 8, and the inlets of the slurry pump 8 are connected with the container 9 that is equipped with the double lye. U-shaped groove separators 10 (vertical arrangement) are fixed on the top, and the upper port of the Nth-stage internal circulation reactor is connected with the flue gas outlet 4, and the flue gas outlet 4 is connected with the inlet of the bag filter 11 through the pipeline The outlet of the bag filter 11 is connected with the inlet of the induced draft fan 12 through the pipeline (the outlet of the induced fan 12 is connected with the chimney 19 through the pipeline), and the ash discharge port at the lower end of the bag filter 11 passes through the ash discharge port. The pipelines are respectively connected with the upper port of the ash storage tank 13 and the ash bin 16, the lower port of the ash storage tank 13 is provided with a screw feeder 14, and the ash discharge port of the screw feeder 14 passes through the discharge port of the ash storage tank 13. The pipe 15 communicates with the throat of the small Venturi tube 2 .

The desulfurizer and ash separated by the U-shaped groove separator at the top of each internal circulation reactor are returned to each internal circulation reactor to form an internal circulation, which promotes the reaction between flue gas and absorbent, and improves the removal of flue gas pollutants efficiency.

The cross-section of each stage of the internal circulation reactor is circular, and the cross-sections of the lower port and the upper port are smaller than the cross-section of the middle section.

Harmful substances in NOx in the flue gas mostly exist in the form of NO, which are oxidized by ClO ₂ to NO ₂ , Hg is oxidized to Hg ²⁺ which is easily soluble in water to generate HgCl _{2 ,} and are removed in the subsequent bag filter 11. Removal; use semi-dry desulfurization technology to remove S0 ₂ and NO ₂ by acid-base neutralization reaction between S0 ₂ and NO ₂ in the flue gas and NaOH + Ca(OH) ₂ aqueous solution in the double lye atomizing nozzle 5 According to the concentration of pollutants in the flue gas, the alkali concentration and the amount of alkali solution in the sprayed solution can be determined.

Specific embodiment two: as shown in Fig. 1, Fig. 2, Fig. 4, Fig. 6 to Fig. 8, the multi-stage internal circulation semi-dry desulfurization, denitrification and demercury integrated device described in specific embodiment 1, each of the U-shaped The groove separator 10 comprises a multilayer U-shaped groove, and several ventilation holes 21 are processed on the side wall of the conical casing 20, and the large-diameter end of the conical casing 20 is provided with an annular outer edge 22, and the conical casing 20 There are multi-layer U-shaped grooves on the outside of the inner layer, and the lower end of the inner U-shaped groove is fixedly connected with the upper surface of the ring-shaped outer edge 22, and the ring-shaped outer edge 22 is processed with openings corresponding to the inner layer U-shaped grooves. , the top in each stage of the internal circulation reactor is fixedly connected to the upper end of the multi-layer U-shaped groove, and each layer of U-shaped grooves includes a plurality of U-shaped groove bodies 23, and a plurality of U-shaped grooves of each layer of U-shaped grooves The groove bodies 23 are located on the same circumference and arranged evenly, and a plurality of U-shaped groove bodies 23 of each adjacent two layers of U-shaped grooves are arranged in a staggered arrangement, and the notches of all U-shaped groove bodies 23 are directed towards the multi-stage inner The side wall of the circulation reactor 3 is set, and the vent hole 21 on the outlet conical shell 20 at the top of each stage of the internal circulation reactor has a diameter of 5 to 6mm, which is set to prevent dust from accumulating, so that the dust can be accumulated Return along the slope to the desulfurization tower to participate in the desulfurization reaction. It is preferred to use two layers of U-shaped grooves inside and outside.

The beneficial effect of this embodiment is: this structural design enables a large amount of material to circulate strongly in each stage of the internal circulation reactor, which not only improves the efficiency of desulfurization and denitrification, but also solves the problem of fouling in each stage of the internal circulation reactor.

Specific embodiment three: as shown in Figure 1, the multi-stage internal circulation semi-dry method desulfurization, denitrification and mercury removal integrated device described in the specific embodiment one or two, the multi-stage internal circulation semi-dry method desulfurization, denitrification and mercury removal integrated device It also includes at least one horizontal guide plate 24; the at least one horizontal guide plate 24 is arranged inside the smoke inlet 1 parallel to the centerline of the smoke inlet 1, and all the horizontal guide plates 24 are fixedly connected to the inner wall of the smoke inlet 1 ( The purpose of setting the horizontal guide plate 24 is to divide the flue gas evenly. After the flue gas passes through the horizontal guide plate 24, it is transported to the large Venturi tube 17, and part of the solid particles fall into the ash under the action of gravity and centrifugal inertial force. hopper 6, and discharged through the ash outlet 18 of the ash hopper 6).

Specific embodiment four: As shown in Figure 1, the multi-stage internal circulation semi-dry method desulfurization, denitrification and mercury removal integrated device described in the specific embodiment three, the multi-stage internal circulation semi-dry method desulfurization, denitrification and mercury removal integrated device also includes At least one vertical guide plate 25 ; the at least one vertical guide plate 25 is arranged in the ash hopper 6 , and all the vertical guide plates 25 are fixedly connected to the inner sidewall of the ash hopper 6 .

Specific embodiment five: as shown in Figure 1, the multi-stage internal circulation semi-dry method desulfurization, denitrification and mercury removal integrated device described in the specific embodiment one, the multi-stage internal circulation semi-dry method desulfurization, denitrification and mercury removal integrated device also includes The flue gas deflector 26; the flue gas outlet 4 forms an angle of 90° with the multi-stage internal circulation reactor 3, the corner of the rectangular flue gas outlet is in the shape of an arc, and the center line in the rectangular flue gas outlet is provided with The flue gas deflector 26 is fixedly connected to the inner wall of the rectangular flue gas outlet (so that the flue gas discharged through the flue gas outlet 4 is uniformly discharged into the bag filter 11 ).

Specific embodiment six: as shown in Figure 1 and Figure 3, the multi-stage internal circulation semi-dry method desulfurization, denitrification and mercury removal integrated device described in the specific embodiment four, the multi-stage internal circulation semi-dry method desulfurization, denitrification and mercury integration The device also includes a rectification grid 27, which includes a plurality of grid plates 28; the rectification grid 27 is fixedly arranged in the throat of the large Venturi tube 17.

The beneficial effect of this embodiment is that the combined use of the horizontal guide plate, the vertical guide plate and the rectifying grill effectively solves the unsolved bias current problem in the prior art.

Working steps of the present invention are: as shown in Figure 1 ~ Figure 8;

Step ₁ , the boiler flue gas enters the flue gas inlet ₁ , first mixes evenly with the ClO2 produced by the ClO2 generator 29, and enters the large Venturi tube 17 after being guided by the horizontal guide plate 24 and the vertical guide plate 25. In the inner pipe 17, it first mixes with the ClO ₂ injected by the ClO ₂ nozzle to undergo an oxidation reaction, part of the SO ₂ is oxidized to SO ₃ , the NO in the flue gas is oxidized to NO ₂ , the Hg is oxidized to Hg ²⁺ , and further The diffusion section of the inner pipe 17 reacts with the double lye absorbent (the double lye is sprayed from the double lye atomizing nozzle ₅ to the accelerated flue gas flow section, which is used to accelerate the SO2 and NO in the absorbent and the flue gas ₂ and other acid gas reactions), the bag filter 11 discharges the circulating ash into the ash storage tank 13, and through the ash discharge port of the screw feeder 14, through the discharge pipe 15, it is accelerated by the small Venturi tube 2 and sprayed into the multi-stage internal circulation In the reactor 3, the flue gas and the absorbent fully react in the multi-stage internal circulation reactor 3, and part of the particles in the flue gas form balls under the spray granulation condition and fall into the ash hopper 6 through the throat of the large venturi 17 Inside, it is discharged through the ash outlet 18;

Step 2: After the flue gas reacts with the absorbent, it is discharged into the bag filter 11 through the flue gas deflector 26 in the flue gas outlet 4 .

The working process of the present invention is: as shown in Fig. 1 ~ Fig. 8, the flue gas from boiler first enters in the flue gas inlet ₁ of the device of the present invention, and the oxidant ClO gas produced by the ClO2 generator is _passed by the _ClO2 distributor 7 Evenly sprayed into the flue gas inlet 1, part of the SO ₂ in the flue gas is oxidized to SO ₃ , NO is oxidized to NO ₂ , Hg is oxidized to Hg ²⁺ , and the flue gas enters through the horizontal guide plate 24 and the vertical guide plate 25 In the entrance of the large Venturi tube 17, a rectifying grille 27 is set in the throat of the large Venturi tube 17, so that the smoke passes through the large Venturi tube 17 evenly without segregation, and the double lye passes through all the double lye atomizing nozzles 5 Spray into the bottom flue gas of each level of internal circulation reactor, the double alkaline solution is composed of Ca(OH) with a mass percentage concentration of 15%~ ₂₅ % and a mass percentage concentration of 0.1%~0.5% NaOH (The purpose is to strengthen the removal of SO ₂ and ensure a desulfurization efficiency of 90%), and the double lye is atomized by compressed air.

Take the three-stage internal circulation reactor as an example: the injection amount of the double lye atomizing nozzle 5 arranged in the diffusion section of the large Venturi tube 17 accounts for 50% of the total amount of the double lye (that is, the amount of smoke sprayed under the rated load The amount of lye in the gas accounts for 50% of the total amount, the same below), and the spraying amount of the double lye atomizing nozzle 5, which is arranged on the lower part of the second-stage internal circulation reactor, accounts for 30% of the total amount of the double lye. In the third-stage internal circulation reactor, the injection amount of the double lye atomizing nozzle 5 in the lower part accounts for 20% of the total amount of the double lye, so that the setting is to ensure that the sprayed slurry is completely evaporated at the outlet of each stage internal circulation reactor , to avoid excessive injection of single-stage slurry, which will cause the slurry to not completely evaporate and flow along the inner wall of the reactor, resulting in serious scaling on the wall surface, affecting safe and stable operation. In order to ensure no condensation in the subsequent bag filter 11, the flue gas temperature at the flue gas outlet 4 of the multi-stage internal circulation reactor 3 is controlled at 85-100°C.

The atomized lime slurry (Ca(OH) ₂ and water) and NaOH solution are converted into steam and wet particles are mixed with the flue gas evenly under the heating of the flue gas, and the neutralization reaction occurs, and the SO ₂ and NO in the flue gas are removed ₂ . The flue gas carries desulfurizers (Ca(OH) ₂ , NaOH) and dust at the top outlet of each stage of the internal circulation reactor. , increase the contact time between flue gas and desulfurizer, strengthen the mixing and turbulence of flue gas and desulfurizer, increase the amount of stock in each stage of internal circulation reactor, increase the concentration of reactants, and increase Ca/S Molar ratio, so that the reaction rate is greatly increased; from the second stage, the smoke velocity at the inlet and outlet ports of each internal circulation reactor is controlled between 10~12m/s, and the middle of each internal circulation reactor The smoke velocity is 4~5m/s. The outlet end of the first-stage internal circulation reactor is the inlet end of the second-stage internal circulation reactor, and the second-stage internal circulation reactor repeats the reaction process of the first-stage internal circulation reactor, and the third-stage internal circulation reactor repeats the reaction process of the first-stage internal circulation reactor. 1. The reaction process of the second-stage internal circulation reactor, after which the flue gas enters the bag filter 11 from the flue gas outlet 4 at the top of the multi-stage internal circulation reactor 3, and part of the ash separated by the bag filter 11 returns to the The ash storage tank 13 is returned to the small Venturi tube 2 through the parallel screw feeder 14 (which is the prior art) and the feeding pipe 15 to form an ash circulation, improve the desulfurization efficiency, and reduce the usage of lime slurry. /S=1.2~1.5; can remove 90% of SO ₂ and more than 80% of NO and Hg.

Reaction principle:

1. The ClO ₂ gas comes to the ClO ₂ generator and reacts with NO, SO ₂ and Hg as follows:

5NO + 2ClO ₂ + H ₂ O = 2HCl + 5NO ₂

5NO ₂ + ClO ₂ + 3H ₂ O = HCl + 5HNO ₃

SO ₂ + 2ClO ₂ + H ₂ O = SO ₃ + 2HCl + 2O ₂

2HCl + Ca(OH) ₂ = CaCl ₂ + 2H ₂ O

2HNO ₃ + Ca(OH) ₂ = Ca(NO ₃ ) ₂ + 2H ₂ O

Hg _{+ 2ClO2} = HgCl2 ₊ 2O2

SO ₃ + Ca(OH) ₂ = CaSO ₄ + H ₂ O

NaOH + HCl = NaCl + _H2O

NaOH + _{HNO3 =} NaNO3 + _H2O

2NaOH+ SO ₃ = Na ₂ SO ₄ + H ₂ O

2. Reaction formula of Ca(OH) ₂ , NaOH and SO ₂ :

Ca(OH) ₂ + SO ₂ = CaSO ₃ 1/2H ₂ O + 1/2H ₂ O

CaSO ₃ + 1/2O ₂ = CaSO ₄

2NaOH ₊ SO2 ₌ Na2SO3 _{+ H2O}

_{2Na2SO3 + O2 = 2Na2SO4}

The specific implementation above is only an embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in this creation. within the scope of protection.

Claims (6)

1. A multi-stage internal circulation semi-dry desulfurization, denitrification and mercury removal integrated device, including a flue gas inlet (1), a small venturi tube (2), a multi-stage internal circulation reactor (3), and a flue gas outlet (4 ), multiple dual lye atomizing nozzles (5), ash hopper ( ₆ ), ClO2 distributor (7), slurry pump (8), container containing dual lye (9), multiple U-shaped troughs Separator (10), bag filter (11), induced draft fan (12), ash storage tank (13), screw feeder (14), feeding pipe (15) and ash bin (16); It is characterized in that: the multi-stage internal circulation reactor (3) is vertically arranged, and the multi-stage internal circulation reactor (3) is sequentially from the first-stage internal circulation reactor to the Nth-stage internal circulation reactor from bottom to top , N is a natural number, and N=3~5; the lower part of the first-stage internal circulation reactor is a large Venturi tube (17), and the large Venturi tube (17) consists of a constriction section, a throat tube and diffusion section; the large Venturi tube (17) is vertically provided with a small Venturi tube (2) between the throat and the diffusion section, and the lower port of the large Venturi tube (17) is connected to the ash hopper ( 6) connected to the upper port, the lower port of the ash hopper (6) is the ash outlet (18), the side wall of the ash hopper (6) is connected to the smoke inlet (1), and the smoke inlet (1) A ClO2 distributor ( ₇ ) is installed inside, and several _ClO2 nozzles of the ClO2 distributor ( ₇ ) spray in the same direction as the flue gas flow, and the large Venturi tube (17) behind the ClO2 distributor ( ₇ ) ) the horizontal guide plate (24) is arranged at the inlet section, and the vertical guide plate (25) is arranged at the lower part of the contraction section of the large venturi tube (17); The lower part of each internal circulation reactor of the multi-stage internal circulation reactor (3) is provided with a double lye atomizing nozzle (5), and the dual lye spray nozzles (5) set in the first-stage internal circulation reactor The atomization nozzles (5) are located in the diffusion section of the large Venturi tube (17), and all the double lye atomization nozzles (5) are located on the center line of the multi-stage internal circulation reactor (3) and are set upwards, and all The inlets of the double lye atomizing nozzles (5) are connected to the outlet of the slurry pump (8), and the inlet of the slurry pump (8) is connected to the container (9) containing the double lye, and each stage U-shaped groove separators (10) are fixed on the top of the internal circulation reactor, and the upper port of the Nth-stage internal circulation reactor is connected with the flue gas outlet (4), and the flue gas outlet (4) is connected to the The inlet of the bag filter (11) is connected, the outlet of the bag filter (11) is connected with the inlet of the induced draft fan (12) through the pipeline, and the ash discharge port at the lower end of the bag filter (11) passes through the ash discharge pipeline Connect with the upper port of the ash storage tank (13) and the ash bin (16) respectively, the lower port of the ash storage tank (13) is provided with a screw feeder (14), and the screw feeder (14 )’s ash discharge port communicates with the throat of the small Venturi tube (2) through the feed pipe (15). 2. According to the multi-stage internal circulation semi-dry desulfurization, denitrification and mercury removal integrated device according to claim 1, it is characterized in that: each U-shaped groove separator (10) includes a conical shell (20) and multiple Layer U-shaped groove, several air holes (21) are processed on the side wall of the conical shell (20), the large diameter end of the conical shell (20) is provided with an annular outer edge (22), the conical shell The outer side of the body (20) is provided with multi-layer U-shaped grooves from the inside to the outside, and the lower end of the inner U-shaped groove is fixedly connected with the upper surface of the annular outer edge (22), and the upper surface of the annular outer edge (22) is connected with the inner U-shaped groove. Openings are processed at the corresponding positions of the tanks, and the top of each stage of the internal circulation reactor is fixedly connected to the upper end of the multi-layer U-shaped tank, and each layer of U-shaped tanks includes a plurality of U-shaped tank bodies (23) , the multiple U-shaped groove bodies (23) of each layer of U-shaped grooves are located on the same circumference and arranged evenly, and the multiple U-shaped groove bodies (23) of every two adjacent layers of U-shaped grooves are arranged in a staggered arrangement, and The notches of all U-shaped tank bodies (23) are arranged towards the side wall of the multistage internal circulation reactor (3). 3. According to claim 1 or 2, the multi-stage internal circulation semi-dry desulfurization, denitrification and mercury integration device is characterized in that: the multi-stage internal circulation semi-dry desulfurization, denitrification and mercury integration device also includes at least one level Guide plate (24); the at least one horizontal guide plate (24) is arranged inside the flue gas inlet (1) parallel to the center line of the flue gas inlet (1), and all horizontal guide plates (24) are connected to the flue gas inlet ( 1) The inner wall is fixedly connected. 4. The multi-stage internal circulation semi-dry integrated device for desulfurization, denitrification and mercury removal according to claim 3, characterized in that: the multi-stage internal circulation semi-dry integrated device for desulfurization, denitrification and mercury removal also includes at least one vertical guide plate (25); the at least one vertical guide plate (25) is arranged in the ash hopper (6), and all the vertical guide plates (25) are fixedly connected to the inner side wall of the ash hopper (6). 5. According to the multi-stage internal circulation semi-dry desulfurization, denitrification and mercury integration device according to claim 1, it is characterized in that: the multi-stage internal circulation semi-dry desulfurization, denitrification and mercury integration device also includes a flue gas deflector (26); the flue gas outlet (4) forms an angle of 90° with the multi-stage internal circulation reactor (3), the corner of the right-angled flue gas outlet is in the shape of an arc, and the center line of the right-angled flue gas outlet is set There is a smoke deflector (26), and the smoke deflector (26) is fixedly connected with the inner wall of the rectangular smoke outlet. 6. According to the multi-stage internal circulation semi-dry desulfurization, denitrification and mercury integration device according to claim 4, it is characterized in that: the multi-stage internal circulation semi-dry desulfurization, denitrification and mercury integration device also includes a rectification grid (27 ), the rectifying grid (27) includes a plurality of grid plates (28); the rectifying grid (27) is fixedly arranged in the throat of the large Venturi tube (17).