CN215311464U - SCR denitration device for high-temperature and high-dust flue gas of cement kiln - Google Patents

Abstract

The utility model discloses an SCR (selective catalytic reduction) denitration device for high-temperature and high-dust flue gas of a cement kiln, which comprises a preheater, a reactor and a waste heat boiler which are sequentially arranged, and also comprises an ammonia water spray gun arranged in the preheater, a guide plate, a rectifying grid and a catalysis layer arranged in the reactor, and a soot blower arranged above the catalysis layer corresponding to each layer. The device ensures good flow field distribution and concentration distribution of the flue gas in the reactor and the overall effect of later cleaning by arranging the flow guide structure. Through designing catalyst structure and soot blowing system, greatly reduced catalyst surface deposition and probability of blockking up reduce the wearing and tearing of catalyst, can keep the relative cleanness of catalyst for a long time, and denitration efficiency is stable high-efficient, guarantees that SCR denitrification facility is long-term, lasts, efficient work on the cement manufacture line.

Description

SCR denitration device for high-temperature and high-dust flue gas of cement kiln

Technical Field

The utility model belongs to the field of cement production equipment, and particularly relates to an SCR denitration device for high-temperature and high-dust flue gas of a cement kiln.

Background

Due to the rapid economic growth of the last forty years, the phenomena of excessive resource consumption and serious decline of air quality in China already occur, so that the improvement of the air quality and the protection of the health of people become important issues in China. In order to improve the quality of atmospheric environment, benefit people and reduce environmental risks, China increases the treatment strength of main atmospheric pollutants and has an initial effect on the treatment of SO2 and other polluted gases. However, the emission of nitrogen oxides, one of the important atmospheric pollutants in China, has not yet been effectively controlled. The monitoring data of the ministry of environmental protection shows that the current acid rain type of China has been changed from the original sulfuric acid type to the sulfuric acid and nitric acid composite type, and the proportion of nitrate ions in the acid rain gradually rises from 1/10 in the 80 th of the 20 th century to 1/3 in the year. The nitrogen oxide can form acid rain, photochemical smog, damage to the ozone layer and other hazards, is a main pollutant in the atmosphere, fully treats the nitrogen oxide, and has very important significance for protecting the ecological environment by perfecting the denitration technology.

At present, the SCR denitration technology is generally adopted in China to deeply treat nitrogen oxides, the Selective Catalytic Reduction (SCR) technology is the mainstream technology for controlling the emission of the nitrogen oxides in a thermal power plant, and ammonia and other reducing agents are sprayed into smoke to react with the nitrogen oxides so as to remove the nitrogen oxides. The denitration technology is commonly provided with technical routes of high temperature and high dust, high temperature medium dust, high temperature micro dust, medium temperature medium dust, low temperature and low dust and the like. However, the SCR denitration technology is not yet widespread in the cement industry, and the flue gas and dust concentration is high and sticky in the cement production process, which easily causes the surface abrasion of the catalyst, the catalyst pore channel is easily blocked by dust particles and ammonium bisulfate crystals, and the heavy metal in the dust easily causes the catalyst poisoning, so the SCR denitration device installed on the cement production line is easily out of service.

SUMMERY OF THE UTILITY MODEL

Aiming at the problem that the existing SCR denitration device cannot be applied to a cement production line, the utility model provides the SCR denitration device for high-temperature and high-dust flue gas of a cement kiln.

The technical purpose is achieved, the technical effect is achieved, and the utility model is realized through the following technical scheme:

the utility model provides a SCR denitrification facility for high-temperature high-dust flue gas of cement kiln, is including preheater, reactor and exhaust-heat boiler that set up in order, still including setting up aqueous ammonia spray gun in the preheater, from going into wind gap to down including guide plate, the rectification grid that sets up in order in the reactor to and a plurality of layers of catalysis layer, and corresponding to each layer the soot blower that catalysis layer set up.

As a further improvement of the utility model, the flue gas inlet end of the preheater is positioned below the preheater, the outlet end of the preheater is positioned above the preheater, and a plurality of cyclones are arranged in an array in the preheater from the flue gas inlet end to the outlet end of the preheater.

As a further improvement of the utility model, the ammonia water spray gun is arranged on one side of the air inlet of the cyclone.

As a further improvement of the utility model, the flue gas inlet end of the reactor is arranged above the reactor, the flue gas inlet of the reactor is communicated with the flue gas outlet of the preheater, and the flue gas outlet end of the reactor is arranged below the reactor.

As a further improvement of the utility model, the bottom end of the reactor is also provided with an ash discharge port.

As a further improvement of the utility model, the cross-sectional area of the flow guide plate is not larger than that of the flow guide grating, the flow guide plate is arranged at the air inlet of the reactor, and the flow guide grating is arranged above the first catalytic layer and is provided with a plurality of layers.

As a further improvement of the utility model, the catalyst is formed by splicing a plurality of catalyst blocks, and the size of the cross section of each catalyst block is 0.9-1.0 m multiplied by 1.8-2.0 m.

As a further improvement of the utility model, the input ends of the blowing pipes of all the blowing devices are connected with the same compressed air source.

As a further improvement of the utility model, a heater is arranged in the air blowing pipeline.

The utility model has the beneficial effects that: the device ensures good flow field distribution and concentration distribution of the flue gas in the reactor and the overall effect of later cleaning by arranging the flow guide structure. Through designing catalyst mechanism and soot blowing system, greatly reduced catalyst surface deposition and probability of blockking up reduce the wearing and tearing of catalyst, can keep the relative cleanness of catalyst for a long time, and denitration efficiency is stable high-efficient, guarantees that SCR denitrification facility is long-term, lasts, efficient work on the cement manufacture line.

Drawings

FIG. 1 is a schematic view of a connection structure of an SCR denitration device according to the present invention;

wherein: 1-preheater, 2-ammonia water spray gun, 3-flue gas pipeline, 4-guide plate, 5-rectification grid, 6-catalyst, 7-reactor, 8-ash discharge port and 9-waste heat boiler.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the utility model and are not intended to limit the utility model.

The following detailed description of the principles of the utility model is provided in connection with the accompanying drawings.

As shown in figure 1, the SCR denitration device for high-temperature and high-dust flue gas of the cement kiln comprises a preheater 1, a reactor 7 and a waste heat boiler 9 which are sequentially arranged and connected through a flue gas pipeline 3, and further comprises an ammonia water spray gun 2 arranged in the preheater 1, a guide plate 4, a rectifying grid 5 and a catalysis layer 6 arranged in the reactor 7, and a soot blower arranged on the catalysis layer 6, wherein the catalysis layer 6 adopts a modular design and is formed by splicing a plurality of catalyst blocks. In the embodiment of the utility model, the cross section area of the single catalyst block is 0.7 multiplied by 1.2m, and the splicing number of the catalyst blocks in the catalyst layer can be adjusted according to the size of the smoke gas, so that the cross section area of the catalyst layer is adjusted.

Starting from an inlet end of an SCR denitration device, namely a preheater 1, a flue gas inlet end of the preheater 1 is positioned below the preheater 1, an outlet end of the preheater 1 is positioned above the preheater 1, and a plurality of C1-grade cyclones are arranged in an array in the preheater 1 from the flue gas inlet end to the outlet end of the preheater 1.

The ammonia water spray gun 2 is arranged on one side of an air inlet of the C1-level cyclone, the reducing agent ammonia water is atomized and then uniformly sprayed into the flue gas, the ammonia gas is evaporated into ammonia gas by virtue of the temperature of the flue gas, and the reducing agent and the flue gas are fully mixed by virtue of the C1 cyclone.

Then the flue gas enters a reactor 7 loaded with a catalyst through a connected flue gas pipeline 3 to carry out catalytic reaction denitration. The two ends of the reactor 7 are conical, the flue gas inlet end of the reactor 7 is arranged above the reactor 7, and the flue gas outlet end of the reactor 7 is arranged below the reactor 7.

The cross-sectional area of the flow guide plate 4 is not larger than that of the rectifying grating 5, the flow guide plate 4 is arranged at the inlet of the reactor 7, the rectifying grating 5 is arranged above the first catalytic layer 6 of the reactor 7, and the distance between every two adjacent catalytic layers 6 is the same. Firstly, under the action of a guide plate 4, the guide plate 4 guides and repeatedly divides the mixed ammonia gas and the flue gas, the flow velocity of the flue gas is reasonably adjusted and improved, and the flow velocity distribution is uniform; then, the flue gas passes through the rectifying grating 5, is rectified and straightened, the flow direction becomes relatively consistent, and when the flue gas moves along the rectifying grating 5 and enters the upper surface of the catalyst layer 6 of the reactor 7, the incident angle of the flue gas flowing in is basically vertical to the direction of the catalyst layer, so that the flowing time of the flue gas passing through the catalyst pore channels is ensured to be consistent, the condition that the individual catalyst pore channels do not react completely is avoided, and the condition that the local abrasion is serious due to overlarge flow speed is also avoided.

The temperature of the flue gas in the reactor 7 is kept at 280-350 ℃, and the flue gas enters the catalyst layer to complete high-efficiency denitration reaction, so that nitrogen oxides are reduced into nitrogen and water.

The flue gas after denitration reaction still has certain waste heat, and the outlet pipeline that will set up at reactor 6 is linked together with exhaust-heat boiler 7, utilizes the flue gas after denitration to carry out waste heat power generation, or arranges according to the place and also can return to other tuber pipes.

Along with the extension of the operation time, high-concentration dust is slowly gathered on the surface of the catalyst, the pore channel of the catalyst layer is easily blocked, at the moment, the soot blower plays a role, the soot blower is used for cleaning the accumulated dust remained on the surface of the catalyst and in the pore channel, and the purified flue gas is connected to the waste heat boiler 9 through the outlet flue. So, efficient catalytic reaction with prevent blockking up simultaneously having, guarantee SCR deNOx systems's high-efficient steady operation. In the embodiment of the utility model, the input ends of the blowing pipelines of all the soot blowers are connected with the same compressed air source, namely an air compressor. And a heater is arranged between the soot blower and the connecting pipeline of the air compressor, the heater is used for heating compressed air in the system starting stage, and the heater does not work when the system normally runs.

The bottom end of the reactor 7 is also provided with an ash discharge port 8, and the ash discharge port 8 is provided with an ash conveying device connected with the existing ash conveying system of the cement plant.

The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the utility model as claimed. The scope of the utility model is defined by the appended claims and equivalents thereof.

Claims (9)

1. The utility model provides a SCR denitrification facility for high-temperature and high-dust flue gas of cement kiln which characterized in that: including preheater, reactor and exhaust-heat boiler that set up in order, still including setting up aqueous ammonia spray gun in the preheater, from income wind gap to down including guide plate, the rectification grid that sets up in order, a plurality of layers of catalysis layer in the reactor, and corresponding to each layer the soot blower that the catalysis layer set up.

2. The SCR denitration device for the high-temperature and high-dust flue gas of the cement kiln as claimed in claim 1, wherein: the flue gas inlet end of the preheater is positioned below the preheater, the outlet end of the preheater is positioned above the preheater, and a plurality of cyclone cylinders are arranged in the preheater from the flue gas inlet end to the outlet end of the preheater in an array mode.

3. The SCR denitration device for the high-temperature and high-dust flue gas of the cement kiln as claimed in claim 2, wherein: the ammonia water spray gun is arranged on one side of the air inlet of the C1 cyclone.

4. The SCR denitration device for the high-temperature and high-dust flue gas of the cement kiln as claimed in claim 1, wherein: the flue gas inlet end of the reactor is arranged above the reactor, the flue gas inlet of the reactor is communicated with the flue gas outlet of the preheater, and the flue gas outlet end of the reactor is arranged below the reactor.

5. The SCR denitration device for the high-temperature and high-dust flue gas of the cement kiln as claimed in claim 4, wherein: the bottom end of the reactor is also provided with an ash discharge port.

6. The SCR denitration device for the high-temperature and high-dust flue gas of the cement kiln as claimed in claim 1, wherein: the cross-sectional area of the guide plate is not larger than that of the rectification grid, the guide plate is arranged at an air inlet of the reactor, and the rectification grid is arranged above the first catalytic layer and is provided with a plurality of layers.

7. The SCR denitration device for the high-temperature and high-dust flue gas of the cement kiln as claimed in claim 1, wherein: the catalyst is formed by splicing a plurality of catalyst modules, and the size of the cross section of each catalyst module is 0.9-1.0 m multiplied by 1.8-2.0 m.

8. The SCR denitration device for the high-temperature and high-dust flue gas of the cement kiln as claimed in claim 1, wherein: the input ends of the air blowing pipelines of all the air blowing devices are connected with the same compressed air source.

9. The SCR denitration device for high-temperature and high-dust flue gas of the cement kiln as claimed in claim 8, wherein: and a heater is arranged in the blowing pipeline.

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