CN102806010A - Variable-flow-direction flue gas catalytic-reduction denitration reactor and denitration method - Google Patents

Abstract

The invention relates to a variable-flow-direction flue gas catalytic-reduction denitration reactor and a denitration method. The reactor consists of a gas inlet passage, flow-direction control passages, a front catalytic-reduction reactor, an inversing area, a dust capturing and auxiliary reducing agent adding area and a back catalytic-reduction reactor, and comprises a first catalyst bed layer, a second catalyst bed layer and a third catalyst bed layer. The flow-direction control passages are arranged on the first catalyst bed layer and the second catalyst bed layer and used for controlling flow direction of gas by regulating two switches synchronously, and the fluid inversing area and the dust capturing and auxiliary reducing agent adding area are combined with the flow-direction control passages. The reactor adopts a sectional fixed bed, temperature distribution within a reaction period is improved by changing flow direction of flue gas at an inlet of the reactor, and components of the low-concentration flue gas can be in catalytic reduction reaction at a uniform and high reduction temperature, catalytic activity of the different catalyst bed layers can be functioned effectively, and flue gas denitration efficiency can be improved.

Description

Flue gas catalytic reduction denitrification reactor with variable flow direction and denitrification method

technical field

The invention relates to the environmental protection field of air pollution control, and is especially suitable for the control of gas phase pollutants in energy fields such as coal conversion and petroleum refining.

Background technique

Nitrogen oxides (NOx for short) are one of the main pollutants in the air. Together with sulfur oxides, they constitute the culprit of acid rain, which not only endangers the natural environment, but also seriously affects human health. Their governance has been gradually incorporated into the environmental protection planning of various countries.

The NOx produced by various coal-fired boilers and catalytic cracking units and emitted with flue gas can reach tens of millions of tons per year. If it is not managed, it will bring great disasters to the earth.

In a nutshell, flue gas denitrification is divided into two categories: wet method and dry method. Except for physical adsorption, the rest are chemical conversion methods. Therefore, the reactor is very important. The denitrification process can also be subdivided into: selective catalytic reduction method (SCR), selective non-catalytic reduction method, photocatalytic oxidation method, red hot carbon reduction method, wet complexation absorption method, plasma method and biological method, etc. Among them, the selective catalytic reduction method occupies an important position in the commercial market due to its technical advantages of high efficiency and low energy consumption.

SCR technology uses various reducing agents, such as ammonia, carbon monoxide, hydrogen or hydrocarbons, to selectively catalytically reduce NOx to nitrogen under medium and low temperature conditions. Englehard Corporation invented the ammonia-based SCR denitrification process in the mid-1950s; about 20 years later, Japan developed a highly active titanium-based vanadium pentoxide SCR catalyst and obtained commercial applications; so far, SCR flue gas denitrification The technology has been widely adopted in developed countries.

Taking ammonia-based SCR denitrification first as an example, the injected ammonia will react exothermicly with NOx and SOx in the reactor as shown in Figure 1. Under the condition of adiabatic operation, the catalyst bed will produce a temperature rise of more than 10°C. The specific temperature rise value depends on the NOx and SOx content, and the conversion rate. For the medium and low temperature denitrification process, using temperature rise to speed up the reaction is an effective means to reduce equipment investment and reduce operating costs.

In order to improve the efficiency of flue gas denitrification, the following factors should be considered when designing the reactor:

1. The temperature and gas velocity distribution of the catalyst bed should be as uniform as possible;

2. The reducing agent and the flue gas are mixed as fully as possible;

3. The conversion rate of NOx should be as high as possible;

4. The pressure drop of the denitration device should be as small as possible;

5. The escape amount of NH3 is as small as possible;

6. The operating cycle should be as long as possible.

Only when the above content is taken into account can the operation of ammonia gas within the explosion limit be prevented, and the problem of catalyst deactivation and regeneration caused by dust and sulfur ammonia attached to the surface of the catalyst can be solved.

The main types of SCR denitration reactors are divided into fixed bed and fluidized bed. Among them, CN100348301C designed a suspended fixed-bed reactor to facilitate the disassembly and assembly of deactivated catalysts; WO2007040308A1 adopted a monolithic catalyst type, which is the mainstream type of fixed-bed catalyst;烟气管道的连接方式；US2011194986A1，CN101219329B，CN202212106U，CN201572607U，CN202212104U在反应器内或外设置了去除烟气中颗粒物的部件；CN100425325C，CN201543395U，CN201244436Y，CN201454414U，CN201543370U，CN202212105U，CN102068904A，CN201807307U，CN201596465U， CN201669060U, CN102309920A designed the conventional structural unit of the reactor; CN202036922U constructed the installation structure of the catalyst; CN101574624B proposed a regenerative reactor, and CN102120129A provided an ammonia injection and mixing device; CN102389838A described a catalyst regeneration Online cleaning device. However, CN1201852C, CN102233232A, CN102026703A, and CN102068906A have designed fluidized bed denitrification reactors. Related patents are numerous.

Davide Fissore et al. (Experimental investigation of the SCR of NOx in simulated moving bed reactor. AIChE Journal, 2006, 52(9): 3146-3154) experimentally studied the SCR denitration reaction in the simulated moving bed. The results show that the simulated moving bed can make the temperature distribution in the reactor uniform, and the denitrification effect is obviously improved. CN2757903Y designed a regenerative SCR denitrification reactor that can change the flow direction, in which the regenerative ceramic part is set separately from the catalyst bed, so that the catalyst bed maintains a relatively high temperature. CN201899983U designed the reactor structure of "C" type rotary flow, which is used to realize the purpose of catalyst cleaning and dust removal.

Contents of the invention

On the basis of synthesizing the above papers and patent ideas, the present invention only sets the catalyst bed to reduce the pressure drop, and designs a switch-type regulating door (referred to as the switch door) inside the reactor, which is controlled by an external drive structure. The periodic operation of variable flow direction of the fixed bed reactor achieves a more uniform temperature distribution in the catalyst bed. This design is different from the three-stage structure of the simulated moving bed, and is more suitable for high-throughput flue gas denitration reactions.

The technical scheme of the variable flow direction flue gas catalytic reduction denitrification reactor of the present invention is as follows:

A variable flow direction flue gas catalytic reduction denitrification reactor 1000, respectively composed of an intake channel 100, a flow direction control channel 200, a front catalytic reactor 300, an inversion area 400, a dust collection and reducing agent auxiliary adding area 500, and a rear The catalytic reactor 600 consists of six parts. The reactor 1000 comprises three stages of catalyst beds, which are respectively the first stage catalyst bed layer 7, the second stage catalyst bed layer 12 and the third stage catalyst bed layer 18, which are characterized in that the first stage catalyst bed layer 7 and the second stage catalyst bed layer A flow direction control channel 200 is provided on the catalyst bed layer 12 of the stage, and the gas flow direction is controlled through the synchronous adjustment of the two switch doors 3 and 13; at the same time, the fluid inversion area 400 and the dust collection and reducing agent auxiliary addition area 500 are combined.

Wherein, the flow control channel 200 is composed of a vertical switch door 3 , a horizontal switch door 13 , a right channel 4 and a left channel 15 . The vertical switch door 3 controls the flow to the two channel inlets at the top of the control channel 200 , and the horizontal switch door 13 controls the flow to the two channel outlets 5 and 14 at the front of the control channel 200 .

The vertical switch door 3 and the horizontal switch door 13 are made of a whole board or a louver structure.

The catalytic reactor 300 is provided with a first-stage catalyst bed 7 and a second-stage catalyst bed 12 side by side, and a soot blower 6 is arranged above the two catalyst beds.

The inversion zone 400 is provided with a baffle plate 9; the baffle plate is on the same plane as the boundary line between the catalyst bed 7 of the first stage and the catalyst bed 12 of the second stage.

The dust collection and reducing agent auxiliary adding area 500 is in the shape of a terrace, and two dust collecting baffles 10 are arranged in it, and a reducing agent auxiliary adding port 11 is arranged between the two dust collecting baffles 10, while the reducing agent The auxiliary inlet 11 is arranged at the center of the terraced bottom.

The post catalytic reactor 600 is provided with a terminal rectification space 16 and a third stage catalyst bed 18 , and the terminal rectification space 16 is connected with the outlet 5 and the outlet 14 which flow to the control channel 200 .

Utilizing the reactor of the present invention to carry out variable flow direction flue gas catalytic reduction denitrification method is that the channel vertical switch door 3 above the right channel 4 and the horizontal switch door 13 in front of the left channel 15 are synchronously adjusted to realize flow direction control; when the vertical switch When the door 3 closes the upper part of the right channel 4, the horizontal switch door 13 closes the front part of the left channel 15 synchronously, and the smoke enters the left channel 15; when the vertical switch door 3 closes the upper part of the left channel 15, the horizontal switch door 13 Synchronously close the front of the right channel 4, the smoke will enter the right channel 4.

The distribution of the fluid is completed in four rectification passages, including the right passage 4, the reverse zone 400, the end rectification space 16 and the left passage 15; the accumulation of the first stage of the catalyst bed 7, the second stage of the catalyst bed 12 and The dust in the catalyst bed 18 of the third stage and the inorganic salts formed after the reaction are periodically removed by the soot blower 6 and the catalyst is regenerated; the reducing agent is injected in two parts, one is in the flue 1, and the other is through the reducing agent Auxiliary join port 11.

When the vertical switch door 3 falls to the upper part of the right channel 4, and the horizontal switch door 13 closes the front part of the left channel 15 synchronously, the smoke enters the left channel 15; under the guidance of the left channel 15, the flow direction is completed. Adjust, and directly enter the second-stage catalyst bed 12 in the pre-catalyzed reactor 300 from top to bottom; the flue gas after this stage of reaction flows into the reverse zone 400, and then turns back into the pre-catalyzed reactor 300 The first stage catalyst bed layer 7 in the middle, then flows into the terminal rectification space 16 by the outlet 5; At this moment, the fluid changes the direction of the main movement again, enters the third stage catalyst bed layer 18 in the rear catalytic reactor 600, and finally flows through the outlet Channel 17 flows out of the reactor 1000;

When the vertical switch door 3 falls to the upper part of the left channel 15, the horizontal switch door 13 closes the front part of the right channel 4 synchronously, and the smoke will enter the right channel 4; after passing through the guide area set in the right channel 4, Entering the first stage of catalyst bed 7, the flue gas after the reaction flows into the reverse zone 400, turns back into the second stage of catalyst bed 12, and then flows into the terminal rectification space 16 from the outlet 14; then, the fluid changes the direction of movement of the main body again, enters The catalyst bed layer 18 of the third stage finally flows out of the reactor 1000 through the outlet channel 17 .

A variable-flow selective catalytic reduction (SCR) reactor 1000 suitable for flue gas denitrification, the main structure of which is shown in FIG. 2 . It is composed of six parts: intake channel 100 , flow control channel 200 , pre-catalytic reactor 300 , inversion zone 400 , dust collection and reducing agent auxiliary addition zone 500 , and post-catalytic reactor 600 .

Figure 3 shows the disassembled structural diagrams of the six parts shown in Figure 2 of the main structure. The intake channel 100 includes a flue 1 and an enlarged section 2; the flow direction control channel 200 is controlled by the vertical switch door 3, the horizontal switch door 13, the right channel 4, the left channel 15, and the vertical switch door 3. The two channel inlets placed at the top of 200, and the two channel outlets placed at the front of 200, controlled by the horizontal switch door 13 to open and close; the pre-catalyzed reactor 300 contains the first catalyst bed 7 and The second catalyst bed layer 12, and the soot blower 6 placed above it; the deflection baffle 9 is provided in the inversion area 400; the dust collection and reducing agent auxiliary addition area 500 is in the shape of a terrace, and dust collection is arranged inside The baffle 10 and the reducing agent auxiliary inlet 11 ; the rear catalytic reactor 600 includes an end rectification space 16 and a third stage catalyst bed 18 , and is connected with a flow control channel 200 . According to the function, the reactor 1000 can be divided into: three catalyst beds are used for SCR reaction, which are respectively the first catalyst bed 7, the second catalyst bed 12 and the third catalyst bed 18, wherein 7 and 12 The structure and size of the two catalyst beds are the same, and they are separated by the separator 8 and arranged in parallel; the flow direction is controlled by the vertical switch door 3 on the channel above the right channel 4, and the horizontal switch door 13 in front of the left channel 15, Synchronous adjustment is realized; the distribution of the fluid is completed in four rectification channels, including the right channel 4, the reverse zone 400, the end rectification space 16 and the left channel 15; the dust accumulated in the catalyst channel and the inorganic salt formed by the reaction Dust removal and catalyst regeneration are realized by soot blower 6 on a regular basis; the reducing agent is injected in two parts, one is in the flue 1, and the other is through the reducing agent auxiliary inlet 11. It is characterized in that: through the synchronous action of the opening and closing gates of the two channels, the periodical variable flow operation of the catalyst beds 8 and 17 is realized.

Instructions for use:

In FIG. 3 , the catalyst bed is divided into three sections, wherein the catalyst bed 7 of the first section and the catalyst bed 12 of the second section are arranged side by side, and are separated by a partition baffle 8 . Before flowing into the control passage 200 , the flue gas containing reducing agent originating from the intake passage 100 can have two choices of flow directions, which are respectively manipulated by the vertical switch door 3 and the horizontal switch door 13 . When the vertical opening and closing door 3 falls to the top of the right passage 4, and the horizontal opening and closing door 13 synchronously closes the front part of the left passage 15, smoke can only enter the left passage 15. Under the guidance of the channel 15 on the left, the adjustment of the flow direction is completed, and it directly enters the second-stage catalyst bed 12 in the front catalytic reactor 300 in the direction indicated by the solid arrow. The flue gas after this stage of reaction flows into the inversion zone 400 , and then turns back into the first stage of the catalyst bed 7 in the front catalytic reactor 300 , and then flows into the terminal rectifying space 16 through the outlet 5 . At this time, the fluid changes the direction of the main body again, enters the catalyst bed 18 of the third stage in the rear catalytic reactor 600 , and finally flows out of the SCR reactor 1000 through the outlet channel 17 . Another option is to reverse the flow direction of the flue gas in the first and second catalyst beds described above, that is, follow the directions of the hollow arrows in FIG. 3 . At this time, the vertical opening and closing door 3 falls to the upper part of the left passage 15, and the horizontal opening and closing door 13 closes the front part of the right passage 4 synchronously, and the smoke will enter the right passage 4. After passing through the guide area set in the right channel 4, it enters the first catalyst bed 7. The flue gas after the reaction flows into the inversion zone 400 , turns back into the catalyst bed 12 of the second stage, and then flows into the rectifying space 16 at the end through the outlet 14 . Subsequently, the fluid changes the direction of the main body again, enters the catalyst bed layer 18 of the third stage, and finally flows out of the reactor 1000 through the outlet channel 17 . The cycle of flow direction switching can be adjusted according to the denitrification result at the outlet of the reactor.

The upper part of the inversion zone 400 and the bottom of the dust collection and reducing agent auxiliary adding zone 500 are respectively provided with deflector baffles 9 and dust collection baffles 10 to meet the purpose of rectification and ammonia dispersion.

The reducing agent ammonia gas is divided into two parts, which enter into the reactor 1000 respectively through the flue 1 and the auxiliary ammonia gas injection port 11 provided separately. Among them, the amount of ammonia gas injected into the auxiliary ammonia gas injection port 11 and the online monitoring of NOx content at the reactor outlet 17 form an adjustment loop, so as to adjust the denitrification effect in time and control the escape amount of ammonia gas.

In order to clean the covering on the surface of the catalyst, a soot blower 6 is specially arranged above the first catalyst bed 7 and the second catalyst bed 12 for dust removal and regeneration of the catalyst.

The transmission mechanism for manipulating the switch door is composed of motor shaft 21, driving gear 19 and driven gear 20, and its enlarged structure is schematically shown in Figure 4. In order to prevent metal-to-metal impact and ensure the sealing effect of the switch door, a non-metallic sealing ring 22 is provided on the upper end and front of the vertical switch door 3 and the horizontal switch door 13 and the right channel 4 and the left channel 15 matched therewith. .

The object of the invention is to design a selective catalytic reduction reactor with variable flow direction for denitrification before flue gas desulfurization. The reactor type of segmented fixed bed is adopted, and the temperature distribution in the reactor is improved by changing the flow direction of the flue gas at the reactor inlet, so that the low-concentration flue gas components can be catalytically reacted at a more uniform and higher reduction temperature . Not only can the catalytic activity of each stage of the catalyst bed be brought into full play, but also the efficiency of flue gas denitrification can be improved.

Compared with the existing fixed-bed reactor with single flow direction, the present invention has the advantages of uniform bed layer temperature, high reaction rate and reduced catalyst consumption. At the same time, the structure of the reactor with variable flow direction and the design of the auxiliary injection port of the reducing agent are added, which simplifies the dust removal and soot blowing methods, and shortens the response time of automatic adjustment. Better meet the basic requirements of flue gas denitrification.

Description of drawings

Figure 1: Reaction and enthalpy diagram;

Figure 2: The main structure of the reactor;

Fig. 3: the structural diagram of each part of the reactor corresponding to Fig. 2;

Figure 4: A partial enlarged view of the transmission mechanism I in Figure 3.

Detailed ways

The present invention is described in further detail according to the accompanying drawings:

A variable flow direction selective catalytic reduction (SCR) reactor suitable for flue gas denitrification, its main structure is shown in Figure 2, which consists of an intake channel 100, a flow control channel 200, a front catalytic reactor 300, and a reverse direction The zone 400 , the dust collection and reducing agent auxiliary adding zone 500 , and the rear catalytic reactor 600 are assembled from six parts.

Figure 3 shows the disassembled structural diagrams of the six parts shown in Figure 2 of the main structure. The intake channel 100 includes a flue 1 and an enlarged section 2; the flow direction control channel 200 is controlled by the vertical switch door 3, the horizontal switch door 13, the right channel 4, the left channel 15, and the vertical switch door 3. It consists of two channel inlets placed at the top of 200, and two channel outlets placed at the front of 200, which are opened and closed by the horizontal switch door 13; the pre-catalyzed reactor 300 contains the first catalyst bed 7, The second catalyst bed layer 12 and the partition 8 between them, and the soot blower 6 placed above it; the deflection baffle 9 is provided in the inversion zone 400; the dust collection and reducing agent auxiliary adding zone 500 It is in the shape of a terrace, with a dust collection baffle 10 and an auxiliary reducing agent inlet 11 inside; the rear catalytic reactor 600 includes a terminal rectification space 16 and a third catalyst bed 18, and is connected to the flow control channel 200. According to the function, it can be divided into: three-stage catalyst bed is used for SCR reaction, which are the first-stage catalyst bed 7, the second-stage catalyst bed 12 and the third-stage catalyst bed 18, of which 7 and 12 are two-stage catalyst The beds have the same structure and size, and are separated by partitions 8 and then arranged in parallel; the flow direction control is realized by synchronous adjustment of the vertical switch door 3 above the channel 4 on the right and the horizontal switch door 13 in front of the channel 15 on the left The distribution of fluid is completed in four rectification passages respectively, including right passage 4, reverse zone 400, end rectification space 16 and left passage 15; the dust and the inorganic salts that are formed by the reaction in the catalyst channel are accumulated on a regular basis by blowing The ash container 6 performs dust removal and catalyst regeneration; the reducing agent is injected in two parts, one in the flue 1, and the other through the reducing agent auxiliary inlet 11. Through the synchronous action of the opening and closing gates of the two channels, the periodical variable flow operation of the catalyst beds 7 and 12 is realized.

Instructions for use:

In FIG. 3 , the catalyst bed is divided into three sections, wherein the catalyst bed 7 of the first section and the catalyst bed 12 of the second section are arranged side by side, and are separated by a partition baffle 8 . Before flowing into the control passage 200 , the flue gas containing reducing agent originating from the intake passage 100 can have two choices of flow directions, which are respectively manipulated by the vertical switch door 3 and the horizontal switch door 13 . When the vertical opening and closing door 3 falls to the top of the right passage 4, and the horizontal opening and closing door 13 synchronously closes the front part of the left passage 15, smoke can only enter the left passage 15. Under the guidance of the channel 15 on the left, the adjustment of the flow direction is completed, and it directly enters the second-stage catalyst bed 12 in the pre-catalyzed reactor 300 in the direction indicated by the solid arrow from top to bottom. The flue gas after this stage of reaction flows into the inversion zone 400 , and then turns back into the first stage catalyst bed 7 in the front catalytic reactor 300 , and then flows into the final rectification space 16 through the outlet 5 . At this time, the fluid changes the direction of the main body again, enters the catalyst bed 18 of the third stage in the rear catalytic reactor 600 , and finally flows out of the SCR reactor 1000 through the outlet channel 17 .

Another option is to reverse the flow direction of the flue gas in the first and second catalyst beds described above, that is, follow the directions of the hollow arrows in FIG. 3 . At this time, the vertical opening and closing door 3 falls to the upper part of the left passage 15, and the horizontal opening and closing door 13 closes the front part of the right passage 4 synchronously, and the smoke will enter the right passage 4. After passing through the guide area set in the right channel 4, it enters the first catalyst bed 7. The flue gas after the reaction flows into the inversion zone 400 , turns back into the catalyst bed 12 of the second stage, and then flows into the rectifying space 16 at the end through the outlet 14 . Subsequently, the fluid changes the direction of the main body again, enters the catalyst bed layer 18 of the third stage, and finally flows out of the reactor 1000 through the outlet channel 17 . The cycle of flow direction switching can be adjusted according to the denitrification result at the outlet of the reactor.

The upper part of the inversion zone 400 and the bottom of the dust collection and reducing agent auxiliary adding zone 500 are respectively provided with deflector baffles 9 and dust collection baffles 10 to meet the purpose of rectification and ammonia dispersion.

The reductant ammonia gas is divided into two parts, which enter into the reactor 1000 respectively through the flue 1 and the separately provided auxiliary reductant injection port 11 . Among them, the amount of ammonia gas injected into the auxiliary reductant injection port 11 and the online monitoring of NOx content at the reactor outlet 17 constitute an adjustment loop, so as to adjust the denitrification effect in time and control the escape amount of ammonia gas.

In order to clean the covering on the surface of the catalyst, a soot blower 6 is specially arranged above the first catalyst bed 7 and the second catalyst bed 12 for dust removal and regeneration of the catalyst.

The transmission mechanism of manipulating the switch door is made of motor shaft 21, driving gear 19 and driven gear 20, and its enlarged structure illustration is shown in Fig. 4 . In order to prevent metal-to-metal impact and ensure the sealing effect of the switch door, a non-metallic sealing ring 22 is provided on the upper end and front of the vertical switch door 3 and the horizontal switch door 13 and the right channel 4 and the left channel 15 matched therewith. .

The present invention adopts periodic operation with variable flow direction. Compared with a fixed-bed reactor with a single flow direction, the temperature distribution of the catalyst bed is more uniform; due to the arrangement of four rectification channels, the mixing of the reducing agent and the flue gas is more sufficient; thereby achieving the same Under the catalyst dosage, the goal of higher NOx conversion rate; the staged addition of the reducing agent not only improves the sensitivity of the self-control, but also reduces the escape of NH ₃ ; the setting of the soot blower is conducive to the long-term operation of the reactor. Therefore, the reactor designed by the present invention meets the requirement of flue gas selective catalytic reduction and denitrification.

Claims (10)

1. A flue gas catalytic reduction denitrification reactor with variable flow direction. The reactor consists of an air intake channel 100, a flow direction control channel 200, a front catalytic reactor 300, an inversion zone 400, and a dust collection and reducing agent auxiliary adding zone 500. , and the post catalytic reactor 600 consists of six parts; the reactor includes three catalyst beds, namely the first catalyst bed (7), the second catalyst bed (12) and the third catalyst bed ( 18), which is characterized in that a flow direction control channel 200 is provided on the first catalyst bed and the second catalyst bed, and the control channel 200 is synchronously adjusted by two switch doors to control the gas flow direction; at the same time, a combination of fluid flow Addition to zone 400 and dust capture and reductant assistance zone 500. 2. The reactor according to claim 1, characterized in that the flow direction control channel 200 is composed of a vertical switch door (3), a horizontal switch door (13), a right channel (4) and a left channel (15), consisting of The vertical switch gate selects the two channel inlets flowing to the top of the control channel 200, and the horizontal switch gate selects the two channel outlets flowing to the front of the control channel 200, thereby limiting the movement direction of the fluid. 3. The reactor according to claim 2, characterized in that the vertical switch door (3) and the horizontal switch door (13) are made of a whole plate or a louver structure. 4. The reactor according to claim 1, characterized in that the pre-catalyzed reactor 300 is provided with a side-by-side first-stage catalyst bed (7) and a second-stage catalyst bed (12), and two-stage catalyst A partition (8) between the beds; a soot blower (6) is arranged above the two catalyst beds. 5. The reactor as claimed in claim 1, characterized in that a baffle baffle 9 is provided in the inversion zone 400; the baffle baffle is connected with the first catalyst bed (7) and the second catalyst bed ( 12) The dividing line is on the same plane. 6. The reactor according to claim 1, characterized in that the area 500 for dust collection and auxiliary adding of reducing agent is in the shape of a terrace, and two dust collection baffles (10) are arranged inside, and the space between the two dust collection baffles is A reducing agent auxiliary inlet (11) is provided. 7. The reactor according to claim 1, characterized in that the rear catalytic reactor 600 is provided with a terminal rectification space (16) and a third catalyst bed (18), and the terminal rectification space and the flow direction control channel 200 The outlet (5) is connected with the outlet (14). 8. The flue gas catalytic reduction denitrification method according to any one of claims 1 to 7, characterized in that the distribution of the fluid is completed in four rectification channels, including the right channel (4), the reverse area 400, and the terminal rectification space ( 16) and the left channel (15); dust and inorganic salts formed after the reaction accumulated in the first catalyst bed (7), the second catalyst bed (12) and the third catalyst bed (18) , dust removal and catalyst regeneration are realized regularly by the soot blower (6); the reducing agent is injected in two parts, one is in the flue (1), and the other is through the reducing agent auxiliary inlet (11). 9. The method according to claim 8, characterized in that the channel vertical switch door (3) above the right channel (4) and the horizontal switch door 13 in front of the left channel (15) are synchronously adjusted to realize flow direction control; When the vertical switch door (3) closes the upper part of the right channel (4), the horizontal switch door (13) closes the front part of the left channel (15) synchronously, and the smoke enters the left channel (15); the vertical switch door ( 3) When the upper part of the left channel (15) is closed, the horizontal switch door (13) closes the front part of the right channel (4) synchronously, and the smoke will enter the right channel (4). 10. The method according to claim 8, characterized in that when the vertical switch door (3) falls to the upper part of the right channel (4), and the horizontal switch door (13) closes the front part of the left channel (15) synchronously , the flue gas enters the left channel (15); under the guidance of the left channel, the flow direction adjustment is completed, and it directly enters the second catalyst bed (12) in the pre-catalytic reactor 300 from top to bottom; The flue gas after this stage of reaction flows into the inversion zone 400, and then turns back into the first catalyst bed layer 7 in the front catalytic reactor 300, and then flows into the terminal rectification space (16) through the outlet (5); at this time , the fluid changes the direction of movement of the main body again, enters the third catalyst bed (18) in the rear catalytic reactor 600, and finally flows out of the reactor 1000 through the outlet channel (17); the vertical switch door (3) is reversed to the left channel (15), and the horizontal switch door (13) synchronously closes the front part of the right passage (4), the smoke will enter the right passage (4); after passing through the guide area set in the right passage, enter The first stage of catalyst bed 7, the flue gas after the reaction flows into the inversion zone 400, turns back into the second stage of catalyst bed (12), and then flows into the terminal rectification space (16) from the outlet (14); then, the fluid changes again The moving direction of the main body enters the catalyst bed (18) of the third stage, and finally flows out of the reactor 1000 through the outlet channel 17.

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