Online regenerative catalytic denitrification and dioxin removal reaction device

Abstract

The present invention provides an on-line regenerative catalytic denitrification and dioxin removal reaction device, which includes an SCR reaction mechanism, a flue gas regeneration mechanism and a desulfurization mechanism. The SCR reaction mechanism includes a plurality of SCR reactors, an ammonia injection assembly and an ammonia-flue gas static mixer. The inlet end of the ammonia-flue gas static mixer is respectively connected to the ammonia injection assembly and the flue gas inlet pipeline, and the outlet pipelines are respectively connected to the inlets of the respective SCR reactors. The inlet end of the flue gas regeneration mechanism is connected to the flue gas exhaust pipeline, and the outlet end is respectively connected to the inlets of the respective SCR reactors. The on-line regenerative catalytic denitrification and dioxin removal reaction device provided by the present invention can not only make the flue gas meet the emission standards by using an integrated catalytic denitrification and dioxin removal catalyst without prior desulfurization by heating, but also can realize on-line regeneration when the catalyst is poisoned and fails due to high-sulfur flue gas.

Description

Technical field:

[0001] The present invention relates to the technical field of denitration reaction, and in particular to an online regenerative catalytic denitration and dioxin removal reaction device. Background technology:

[0002] In the subsequent flue gas treatment systems of many domestic hazardous waste and chemical incineration devices, they all face the same dilemma, that is, due to the complex types of hazardous wastes involved in the incineration and their high sulfur and nitrogen contents, a large amount of nitrogen oxides and sulfur dioxide will be produced during the incineration process. In order to achieve standard flue gas emissions, denitrification must be carried out. However, in order to make the catalytic denitrification catalyst reach the best efficiency, the traditional process is to remove sulfur dioxide from the flue gas to below 50mg / NM3, and then heat the desulfurized flue gas to about 180-200℃ for catalytic denitrification. Although this traditional process can also achieve standard flue gas emissions, its operation is not economical and the production cost is high. Summary of the invention:

[0003] The purpose of the present invention is to provide an online regenerative catalytic denitrification and dioxin removal reaction device that can solve the above problems in view of the defects of the prior art.

[0004] The technical solution to achieve the purpose of the present invention is: an online regenerative catalytic denitrification and dioxin removal reaction device, including an SCR reaction mechanism, a flue gas regeneration mechanism and a desulfurization mechanism.

[0005] The SCR reaction mechanism includes a plurality of SCR reactors, an ammonia injection assembly and an ammonia-flue gas static mixer. The inlet end of the ammonia-flue gas static mixer is respectively connected to the ammonia injection assembly and the flue gas intake pipe. The outlet pipe of the ammonia-flue gas static mixer includes a plurality of first branch pipes. Each of the first branch pipes is respectively connected to the inlet of each SCR reactor, and each of the first branch pipes is provided with a first control valve. The outlet pipes of each SCR reactor are respectively connected to the flue gas exhaust pipe. A composite functional catalyst layer is provided in the SCR reactor.

[0006] The inlet end of the flue gas regeneration mechanism is connected to the flue gas exhaust pipe, and the outlet end includes a plurality of second branch pipes, each of which is respectively connected to the inlet of each SCR reactor, and each of the second branch pipes is respectively provided with an electric regulating valve, and a flue gas heating mechanism is provided in the flue gas regeneration mechanism.

[0007] The inlet of the desulfurization mechanism is connected to the flue gas exhaust duct, and an induced draft fan is provided on the flue gas exhaust duct.

[0008] Further, the ammonia injection assembly includes an ammonia gas tank, an ammonia gas mixer, a dilution blower, and an ammonia injection grid. The inlet of the ammonia gas mixer is connected to the ammonia gas tank and the dilution blower, and the outlet end is connected to the ammonia injection grid. The ammonia injection grid is connected to the inlet end of the ammonia-smoke static mixer.

[0009] Further, to facilitate ash cleaning of the catalyst layer, the reaction device further includes a soot blowing mechanism. The soot blowing mechanism includes a compressed air source and a soot blowing end. The soot blowing end is connected to the compressed air source through a pipeline and is correspondingly arranged above the composite functional catalyst layer. The soot blowing end is a rake-type on-line mobile soot blowing device, and a plurality of soot blowing ports are provided thereon.

[0010] Further, the number of SCR reactors is 3.

[0011] Further, a second control valve is provided on the outlet pipeline of each SCR reaction.

[0012] Further, to relieve the environmental pressure and enhance the catalytic effect of the catalyst, a bag filter is provided between the flue gas inlet pipeline and the ammonia-smoke static mixer. The inlet of the bag filter is connected to the flue gas inlet pipeline, and the outlet of the bag filter is connected to the inlet end of the ammonia-smoke static mixer.

[0013] The beneficial effects of the on-line regeneration catalytic denitration and dioxin removal reaction device of the present invention are as follows:

[0014] (1) The present invention provides an on-line regeneration catalytic denitration and dioxin removal reaction device. Through the mutual cooperation of the SCR reaction mechanism, the flue gas regeneration mechanism, and the desulfurization mechanism, without prior heating for desulfurization, an integrated low-temperature catalytic denitration and dioxin removal catalyst is used, which not only denitrates but also can remove dioxin to make the flue gas meet the emission standards; when the catalyst is poisoned and fails due to high-sulfur flue gas, on-line regeneration can be achieved.

[0015] (2) An electric control valve is installed at the hot flue gas regeneration inlet of each SCR reactor, which can automatically switch the regeneration according to the PLC control level; a small amount of hot flue gas is extracted from the system and heated to 350°C by a heating mechanism in the flue gas regeneration mechanism and then sent into the failed SCR reactor for regeneration. When the flue gas regeneration of the failed SCR reactor ends, it automatically switches to another failed SCR reactor. The first control valve on the first shunt pipeline of the other failed SCR reactor closes, and the 350°C hot flue gas enters this failed reactor for regeneration. At the same time, the first control valve of the just regenerated SCR reactor opens to carry out the denitrification reaction to remove dioxins. Such cyclic reactions are carried out in several towers to ensure that there is always one SCR reactor in regeneration among several SCR reactors, and the other SCR reactors are working, without affecting the denitrification of flue gas and the efficiency of removing dioxins, and realizing the up-to-standard discharge of flue gas. BRIEF DESCRIPTION OF THE DRAWINGS:

[0016] Figure 1 It is a schematic structural diagram of the present invention.

[0017] In the figure: 1 SCR reaction mechanism, 11 SCR reactor, 111 composite function catalyst layer, 12 outlet pipeline, 121 second control valve, 13 first shunt pipeline, 131 first control valve, 14 flue gas inlet pipeline, 15 bag filter, 16 ammonia-flue gas static mixer, 17 induced draft fan, 18 ammonia injection assembly, 181 dilution fan, 182 ammonia gas tank, 183 ammonia gas mixer, 184 ammonia injection grid, 19 flue gas exhaust pipeline, 2 flue gas regeneration mechanism, 21 second shunt pipeline, 22 electric control valve, 3 desulfurization mechanism, 4 soot blowing mechanism, 41 compressed air source, 42 soot blowing port, 43 soot blowing end. DETAILED DESCRIPTION OF THE EMBODIMENTS:

[0018] The following elaborates on the preferred embodiments of the present invention in conjunction with the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0019] See Figure 1 , an on-line regenerative catalytic denitrification and dioxin removal reaction device, comprising an SCR reaction mechanism 1, a flue gas regeneration mechanism 2 and a desulfurization mechanism 3.

[0020] The SCR reaction mechanism 1 includes a number of SCR reactors 11, an ammonia injection assembly 18, and an ammonia-flue gas static mixer 16. The inlet end of the ammonia-flue gas static mixer 16 is respectively connected to the ammonia injection assembly 18 and the flue gas inlet pipe 14. The outlet pipe of the ammonia-flue gas static mixer 16 includes a plurality of first shunt pipes 13, and each of the first shunt pipes 13 is respectively connected to the inlet of each SCR reactor 11. A first control valve 131 is provided on each of the first shunt pipes 13. The outlet pipes 12 of each SCR reactor 11 are respectively connected to the flue gas exhaust pipe 19. In order to facilitate the control of the exhaust situation, a second control valve 121 can be provided on the outlet pipe 12 of each SCR reactor 11. A composite functional catalyst layer 111 is provided in the SCR reactor 11.

[0021] In addition, the number of the SCR reactors 11 can be set according to specific conditions, and preferably is 3. The SCR reactor 11 is a structure containing a catalyst, mainly formed by welding a steel structure frame, steel plates, etc. to form a sealed space. In order to prevent the heat dissipation of the flue gas, heat preservation materials and steam heating tracing pipes can be arranged between the inner and outer protection plates of the SCR reactor 11.

[0022] Since the flue gas with high nitrogen oxides contains high sulfur dioxide gas, the sulfur dioxide gas will react with ammonia in the reactor to generate ammonium bisulfate. Therefore, in order to prevent the generated ammonium bisulfate (ABS) from depositing on the surface of the composite functional catalyst (ABS has a melting point of 147 degrees and decomposes at a temperature above 280 degrees. At low temperatures, ABS has specific viscosity and will aggregate with the soot in the flue gas and deposit on the surface of the composite functional catalyst, blocking the small holes on the catalyst surface, affecting the catalyst activity and causing the system to be over-pressurized and unable to operate normally), a flue gas regeneration mechanism 2 needs to be configured in the SCR reactor 11. When the nitrogen oxide concentration in the flue gas exhaust pipe 19 is too high, the flue gas regeneration mechanism 2 is started to perform hot flue gas regeneration on the SCR reactor 11 that has failed due to ABS. The regeneration source of the SCR reactor 11 this time adopts clean flue gas at 180 - 200 degrees that has undergone primary denitrification and dioxin treatment.

[0023] The inlet end of the flue gas regeneration mechanism 2 is connected to the flue gas exhaust pipe 19, and the outlet end includes a plurality of second shunt pipes 21. Each of the second shunt pipes 21 is respectively connected to the inlet of each SCR reactor 11. An electric control valve 22 is respectively provided on each of the second shunt pipes 21. A flue gas heating mechanism (not shown in the figure) is provided in the flue gas regeneration mechanism 2.

[0024] Since an electric control valve 22 is installed at the regeneration air inlet of each SCR reactor 11, the regeneration can be automatically switched according to the PLC control level; the regenerative hot flue gas uses the 180-200°C hot flue gas of the reaction system as the regeneration source, and a small amount of hot flue gas is extracted from the system and heated to 350°C in the regeneration mechanism 2 and then sent into the failed SCR reactor 11 for catalyst regeneration; when the regeneration of the failed SCR reactor 11 is completed, it is automatically switched to another failed SCR reactor 11, and the control valve 131 on the main flue gas pipeline, i.e., the first shunt pipeline 13, of the other failed SCR reactor 11 is closed, and the 350°C hot flue gas enters this SCR reactor 11 for regeneration. At the same time, the flue gas inlet valve of the just regenerated SCR reactor 11, i.e., the control valve 131, is opened to carry out the denitrification reaction to remove dioxins. In this way, several SCR reactors 11 cycle and react to ensure that there is always one SCR reactor in regeneration and the other SCR reactors are working. The entire regeneration process runs fully automatically, and the regeneration time can be corrected in a timely manner according to the incineration conditions and the actual operating conditions.

[0025] The inlet of the desulfurization mechanism 3 is connected to the flue gas exhaust pipeline 19, and an induced draft fan 17 is provided on the flue gas exhaust pipeline 19.

[0026] In addition, the ammonia injection assembly 18 of the present application includes an ammonia gas tank 182, an ammonia gas mixer 183, a dilution fan 181, and an ammonia injection grid 184. The inlet of the ammonia gas mixer 183 is connected to the ammonia gas tank 182 and the dilution fan 181, and the outlet end is connected to the ammonia injection grid 184. The ammonia injection grid 184 is connected to the inlet end of the ammonia-gas static mixer 16. After the ammonia gas is diluted by air, it is mixed with the flue gas in the ammonia-gas static mixer 16, and after being evenly mixed, it enters the SCR reactor 11.

[0027] In addition, the ammonia injection system of our party fully considers its safety. Since the explosion upper and lower limits of ammonia are 16%-25%, before injecting ammonia into the SCR denitrification and dioxin removal reaction tower, our party will dilute it to 1 / 4 of the lower explosion concentration limit and then inject it; at the same time, during the entire denitrification process, the system strictly controls the injection amount of ammonia gas. While ensuring the complete conversion of nitrogen oxides, the ammonia is not excessively ingested, and no secondary pollution is caused to the environment. The injection amount of ammonia gas is interlocked with a pneumatic flow control valve and an ammonia gas flow meter. The measurement of the ammonia gas flow meter is interlocked with the nitrogen oxide concentration analyzer at the outlet of the SCR reaction tower, and is also interlocked with the on-line ammonia gas analyzer at the outlet of the SCR reactor 11, strictly controlling the outlet concentration of ammonia at the outlet to ≤3PPm to ensure that the ammonia is not excessive.

[0028] In addition, in order to facilitate the cleaning of the catalyst layer, the reaction device also includes a soot blowing mechanism 4, which includes a compressed air source 41 and a soot blowing end 43. The soot blowing end 43 is connected to the compressed air source 41 through a pipeline. The soot blowing end 43 is a rake-type online mobile soot blowing device, which is correspondingly arranged above the composite functional catalyst layer 111. The soot blowing end 43 is provided with a plurality of soot blowing ports 42. At the same time, the compressed air can be heated to about 150-160°C by the flue gas heater (not shown in the figure) inside the SCR system and then blown into the composite functional catalyst layer 111 for cleaning, so as to avoid the temperature drop in the SCR reactor 11 caused by the injection of compressed air. At the same time, a differential pressure transmitter can be installed on each layer of the composite functional catalyst layer 111, and the soot blowing control system is controlled by combining differential pressure with time, which can be flexibly controlled.

[0029] In addition, in order to reduce environmental pressure and enhance the catalytic effect of the catalyst, a bag dust collector 15 is provided between the flue gas intake duct 14 and the ammonia-flue gas static mixer 16. The bag dust collector 15 can first remove most of the dust in the flue gas. The inlet of the bag dust collector 15 is connected to the flue gas intake duct 14, and the outlet of the bag dust collector 15 is connected to the inlet end of the ammonia-flue gas static mixer 16.

[0030] When the present application is working, the flue gas enters the bag filter 15 from the flue gas intake duct 14, enters the ammonia-flue gas static mixer 16 after dust removal to be evenly mixed with the diluted ammonia, and then enters each SCR reactor 11 to perform denitration and dioxin removal reactions, and the gas after the reaction continues to enter the desulfurization mechanism 3 for desulfurization, and the gas that meets the standards after desulfurization is discharged through the outlet of the desulfurization mechanism 3. During the reaction process, when it is detected that the nitrogen and oxygen concentration in the flue gas exhaust duct 19 is too high, the flue gas regeneration mechanism 2 is started to perform hot flue gas regeneration on the SCR reactor 11 that has failed due to ABS, and several SCR reactors 11 work in a cyclic reaction to ensure that there is always one SCR reactor 11 in the regeneration among several SCR reactors, and the other SCR reactors 11 are working.

[0031] The above-mentioned embodiments only express several implementation methods of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. An on-line regenerative catalytic denitrification and dioxin removal reaction device, characterized in that: it includes an SCR reaction mechanism (1), a flue gas regeneration mechanism (2) and a desulfurization mechanism (3), the SCR reaction mechanism (1) includes a plurality of SCR reactors (11), an ammonia injection assembly (18) and an ammonia-flue gas static mixer (16). The inlet end of the ammonia-flue gas static mixer (16) is respectively connected to the ammonia injection assembly (18) and a flue gas inlet pipe (14). The outlet pipe of the ammonia-flue gas static mixer (16) includes a plurality of first shunt pipes (13). Each of the first shunt pipes (13) is respectively connected to the inlet of each SCR reactor (11), and a first control valve (131) is provided on each of the first shunt pipes (13). The outlet pipes (12) of each SCR reactor (11) are respectively connected to a flue gas exhaust pipe (19). A composite functional catalyst layer (111) is provided in the SCR reactor (11), a bag filter (15) is provided between the flue gas inlet pipe (14) and the ammonia-flue gas static mixer (16). The inlet of the bag filter (15) is connected to the flue gas inlet pipe (14), and the outlet of the bag filter (15) is connected to the inlet end of the ammonia-flue gas static mixer (16), the inlet end of the flue gas regeneration mechanism (2) is connected to the flue gas exhaust pipe (19), and the outlet end includes a plurality of second shunt pipes (21). Each of the second shunt pipes (21) is respectively connected to the inlet of each SCR reactor (11), and an electric control valve (22) is provided on each of the second shunt pipes (21). A flue gas heating mechanism is provided in the flue gas regeneration mechanism (2), the inlet of the desulfurization mechanism (3) is connected to the flue gas exhaust pipe (19), and an induced draft fan (17) is provided on the flue gas exhaust pipe (19), the reaction device further includes a soot blowing mechanism (4). The soot blowing mechanism (4) includes a compressed air source (41) and a soot blowing end (43). The soot blowing end (43) is connected to the compressed air source (41) through a pipe and is correspondingly arranged above the composite functional catalyst layer (111). The soot blowing end (43) is a rake-type on-line mobile soot blowing device, and a plurality of soot blowing ports (42) are provided thereon.

2. The on-line regenerative catalytic denitrification and dioxin removal reaction device according to claim 1, characterized in that: the ammonia injection assembly (18) includes an ammonia gas tank (182), an ammonia gas mixer (183), a dilution fan (181) and an ammonia injection grid (184). The inlet of the ammonia gas mixer (183) is connected to the ammonia gas tank (182) and the dilution fan (181), and the outlet end is connected to the ammonia injection grid (184). The ammonia injection grid (184) is connected to the inlet end of the ammonia-flue gas static mixer (16).

3. The on-line regenerative catalytic denitrification and dioxin removal reaction device according to claim 1, characterized in that: the number of the SCR reactors (11) is 3.

4. The on-line regenerative catalytic denitration and dioxin removal reaction device according to claim 1, characterized in that: a second control valve (121) is provided on the outlet pipe (12) of each SCR reactor (11).

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