Flue gas denitration equipment for enamel material production line

Abstract

The utility model relates to the field of inorganic chemical industry production and flue gas denitration, and provides enamel material production line flue gas denitration equipment which comprises a flue gas temperature control system, a dust removal pretreatment system, a catalytic denitration system and a reducing agent supply system which are connected through a pipeline, and the flue gas temperature control system is connected with a flue gas inlet through a pipeline; the flue gas temperature control system comprises a coil pipe type surface cooler, a water sprayer, a cold air system and temperature transmitters which are arranged on a pipeline, and the temperature transmitters comprise a first transmitter and a second transmitter which are arranged at the front ends of the water sprayer and the cold air system in the flue gas advancing direction respectively. The flue gas temperature monitoring device is used for monitoring flue gas temperature and adjusting cooling operation of the water sprayer and the cold air system. According to the utility model, the temperature of high-temperature flue gas is stably controlled within a specified required value through three-stage temperature regulation and control measures, then the flue gas enters the bag-type dust collector, the bag-type dust collection effect is not damaged, and the high-efficiency denitration efficiency can be ensured by adopting a specially-made medium-low-temperature efficient denitration catalyst and arranging in a multi-layer manner.

Description

Technical Field

[0001] The utility model relates to the fields of inorganic chemical production and flue gas denitration, in particular to a flue gas denitration device for an enamel material production line. Background Art

[0002] Taking quartz, feldspar, soda ash, borax, titanium oxide, nitrate, etc. as raw materials and natural gas as fuel, calcining and melting are carried out in an industrial furnace to produce enamel materials. Although the flue gas of the furnace does not contain sulfur dioxide, it contains a high concentration of nitrogen oxides, generally up to 2000 - 3000 mg / m 3 . At the same time, it also contains soot, fluorides, etc. The soot also contains alkali metals and alkaline earth metal components such as sodium, calcium, and magnesium. Fluorides and sodium, calcium, magnesium, etc. have great poisoning effects on the catalyst for selective catalytic denitration. After running for a certain period of time, the catalyst will cause chemical bond breakage and recombination, resulting in the collapse and fragmentation of the catalyst, or the formation of molten substances adhering to the surface of the catalyst to form blockages. This makes the denitration device unable to operate normally or become ineffective in a short time. How to solve the above problems and enable the denitration device to operate normally for a long time is a topic for environmental protection technical workers to study. Summary of the Utility Model

[0003] The purpose of the utility model is to overcome the above deficiencies of the prior art and provide a flue gas denitration device for an enamel material production line that can prevent molten substances from adhering to the surface of the catalyst, avoid blocking the catalyst, ensure the long-term normal operation of the equipment, and effectively denitrate.

[0004] The technical solution of the utility model is: a flue gas denitration device for an enamel material production line, including a flue gas temperature control system, a dust removal pretreatment system, a catalytic denitration system, and a reductant supply system connected by pipelines. The flue gas temperature control system is connected to the flue gas inlet through a pipeline. The flue gas temperature control system includes a coil surface cooler, a water sprayer, a cold air system, and a temperature transmitter arranged on the pipeline. The temperature transmitter includes a first transmitter and a second transmitter respectively arranged at the front end of the water sprayer and the cold air system in the flue gas traveling direction, for monitoring the flue gas temperature and adjusting the cooling operations of the water sprayer and the cold air system.

[0005] The flue gas temperature at the kiln outlet is 400 - 800 °C. The kiln flue gas is connected to a coil - type surface cooler. A water sprayer is first connected to the outlet flue of the surface cooler, then a transmitter, then a cold air system, and finally a second transmitter. Thus, the flue gas temperature is controlled through three - stage regulation to ensure that the flue gas temperature is about 240 °C, so as to meet the requirements of subsequent dust removal and denitration systems, ensuring both efficiency and safety. If the initial flue gas temperature in the kiln is not too high, the requirement can be met after surface cooling. If the initial flue gas temperature is too high and still does not meet the requirement after passing through the surface cooler, the connected water sprayer is turned on for spraying to cool down the temperature. To prevent production abnormalities from causing an extremely high furnace temperature, or water sprayer failures or water cut - off, resulting in an instantaneous excessive flue gas temperature that burns out the subsequent dust removal filter bags, a cold air system is added to prevent the sudden high temperature from burning out the dust removal pretreatment system.

[0006] Furthermore, the surface cooler is a folded - back flue assembly made of thin steel plates, which increases the heat dissipation area and significantly reduces the temperature of the high - temperature flue gas just coming out of the kiln.

[0007] Furthermore, the water sprayer includes a spray water pipe, a regulating valve, and a nozzle. The regulating valve is linked with the first transmitter for control. When the flue gas temperature is high, the valve opening is increased; when the flue gas temperature is low, the valve is closed or the opening is reduced.

[0008] Furthermore, the cold air system includes a cold air pipe, a cold air valve, a flue mixer, and a second transmitter. The cold air valve is arranged on the cold air pipe, the cold air pipe is connected to the flue mixer, and the second transmitter is arranged at the front end of the flue mixer. The cold air valve is usually completely closed. When the first transmitter detects abnormal flue gas temperature, the cold air valve is fully opened to prevent the sudden high temperature from burning out the dust removal pretreatment system. The cold air valve is adjusted according to the detection result of the second transmitter to control the flue gas temperature within the required range.

[0009] Furthermore, the dust removal pretreatment system includes a first expansion joint, a dust collector box body, and a second expansion joint. The first expansion joint and the second expansion joint are respectively arranged at the inlet and outlet of the dust collector box body. The dust collector box body is provided with dust removal filter bags and a pulse back - blowing device. Preferably, the dust removal filter bags are made of a new type of high - efficiency bag with all - PDFE material, with an instantaneous temperature resistance of 280 °C, a long - term working temperature of up to 260 °C, and are wear - resistant, corrosion - resistant, and durable.

[0010] Furthermore, the catalytic denitration system includes a denitration reactor. The two ends of the denitration reactor are provided with an inlet flue and an outlet flue. The third expansion joint and the fourth expansion joint are respectively arranged on the inlet flue and the outlet flue. The denitration reactor is provided with a flow equalizer and denitration catalyst. The flow equalizer is arranged at the rear end in the direction of the flue gas flow, and the denitration catalyst is arranged at the front end in the direction of the flue gas flow.

[0011] Preferably, a third transmitter and a fourth transmitter are respectively arranged on the inlet flue and the outlet flue.

[0012] Furthermore, an acoustic soot blower is provided on the denitration reactor, and at least three layers of denitration catalysts are provided. The acoustic soot blower is used to blow soot on each layer of denitration catalyst.

[0013] Preferably, the denitration catalyst is a medium- and low-temperature vanadium-based honeycomb catalyst with a model of 30 holes or more. Three layers are provided. When the efficiency decreases after running for a certain period or when the catalyst layers are rotated and replaced, the remaining layer is additionally installed. Since the flue gas has been dust-removed and the dust concentration is already very low, there is no need to use a pneumatic rake soot blower, and only a simple acoustic soot blower is required.

[0014] Furthermore, an ammonia injection grid is provided on the inlet flue. The ammonia injection grid is located at the rear end of the intake direction of the third expansion joint. The ammonia injection grid is connected to the reducing agent supply system.

[0015] Furthermore, the reducing agent supply system includes a preparation device, an ammonia-air mixing device, and a bellows. The preparation device is connected to the ammonia-air mixing device. The ammonia-air mixing device is connected to the ammonia injection grid through a pipeline. A regulating valve, a flow meter, and a bellows are provided on the pipeline. At least 3 groups of ammonia injection grids are provided.

[0016] Furthermore, the outlet flue is connected to the subsequent flue gas treatment system through a pipeline. A branch is provided on the pipeline. A dilution fan and a dilution damper are provided on the branch. The dilution damper is provided at the outlet end of the dilution fan. The dilution damper is connected to the ammonia-air mixing device through a pipeline.

[0017] The utility model has the following characteristics:

[0018] 1. The utility model stably controls the temperature of the high-temperature flue gas within the specified required value through three-stage temperature control measures and then enters the bag filter, ensuring that the bag is not damaged to guarantee the dust removal effect.

[0019] 2. Through cooling and a long residence time, hydrogen fluoride in the flue gas can form solid substances such as calcium fluoride and magnesium fluoride. These can be captured by the dust collector, and the dust collector can also capture salts such as alkali metals or alkaline earth metals in the flue gas; the poisoning effect of these harmful components on the denitration catalyst is eliminated, ensuring that the denitration catalyst is not damaged, thereby achieving long-term stable operation.

[0020] 3. A special medium- and low-temperature high-efficiency denitration catalyst is adopted and arranged in multiple layers, which can ensure high denitration efficiency.

[0021] The detailed structure of the utility model is further described below in conjunction with the drawings and specific embodiments. Description of the Drawings

[0022] Figure 1 It is a schematic structural diagram of the utility model.

[0023] 1 - Furnace flue gas, 2 - Surface cooler, 3 - Water sprayer, 4 - Cold air system, 5 - Flue mixer, 6 - First expansion joint, 7 - Bag filter, 8 - Inlet flue, 9 - Denitration reactor, 10 - Flow equalizer, 11 - Denitration catalyst, 12 - Subsequent flue gas treatment system, 13 - Dilution fan, 14 - Dilution damper, 15 - Reductant supply system, 16 - Ammonia-air mixing device, 17 - Control valve, 18 - Flowmeter, 19 - Bellows, 20 - Ammonia injection grid, 21 - Valve, 22 - Sonic soot blower, 23 - Compressed air supply system, 24 - First transmitter, 25 - Second expansion joint, 26 - Third expansion joint, 27 - Fourth expansion joint, 28 - Outlet flue, 29 - Second transmitter, 30 - Third transmitter, 31 - Fourth transmitter. Detailed implementation mode

[0024] Embodiment 1

[0025] As shown in the attached drawings: A flue gas denitration device for an enamel material production line includes a flue gas temperature control system, a dust removal pretreatment system, a catalytic denitration system, and a reductant supply system 15 connected by pipelines. The flue gas temperature control system is connected to the flue gas inlet through a pipeline. The flue gas temperature control system includes a coil-type surface cooler 2, a water sprayer 3, a cold air system 4, and a temperature transmitter arranged on the pipeline. The temperature transmitter includes a first transmitter 24 and a second transmitter 29 respectively arranged at the front end of the water sprayer 3 and the cold air system 4 in the flue gas traveling direction, for monitoring the flue gas temperature and adjusting the cooling operations of the water sprayer 3 and the cold air system 4.

[0026] The flue gas temperature at the furnace outlet is 400 - 800 °C. The furnace flue gas 1 is connected to the coil-type surface cooler 2. The water sprayer 3 is first connected to the outlet flue 28 of the surface cooler 2, then a transmitter is connected, and then the cold air system 4 is connected, and finally the second transmitter 29 is connected. Thus, the flue gas temperature is controlled through three adjustments to ensure that the flue gas temperature is about 240 °C, so as to meet the requirements of the subsequent dust removal and denitration systems, ensuring both efficiency and safety. If the initial flue gas temperature in the furnace is not too high, the requirements can be met after surface cooling. If the initial flue gas temperature is too high and still does not meet the requirements after passing through the surface cooler 2, the subsequent water sprayer 3 is turned on for spraying water to cool down. To prevent production abnormalities from causing extremely high furnace temperatures, or malfunctions or water cut-off of the water sprayer 3, resulting in instantaneous overheating of the flue gas temperature and burning out the subsequent dust removal filter bags, a cold air system 4 is added to prevent sudden high temperatures from burning out the dust removal pretreatment system.

[0027] In an embodiment, the surface cooler 2 is a folded flue assembly made of thin steel plates, which increases the heat dissipation area and significantly reduces the temperature of the high-temperature flue gas just coming out of the kiln. The water sprayer 3 includes a spray water pipe, a regulating valve 17 and nozzles. The regulating valve 17 is linked and controlled with the first transmitter 24. When the flue gas temperature is high, the valve opening is increased; when the flue gas temperature is low, the valve is closed or shut down. The cold air system 4 includes a cold air pipe, a cold air valve, a flue mixer 5 and a second transmitter 29. The cold air valve is arranged on the cold air pipe, the cold air pipe is connected to the flue mixer 5, and the second transmitter 29 is arranged at the front end of the flue mixer 5. The cold air valve is normally completely closed. When the first transmitter 24 detects abnormal flue gas temperature, the cold air valve is completely opened to prevent the dust removal pretreatment system from being burned out by sudden high temperature. The cold air valve is adjusted according to the detection result of the second transmitter 29 to control the flue gas temperature within the required range.

[0028] In an embodiment, the dust removal pretreatment system includes a first expansion joint 6, a dust collector box body and a second expansion joint 25. The first expansion joint 6 and the second expansion joint 25 are respectively arranged at the inlet and outlet of the dust collector box body. The dust collector box body is provided with dust removal filter bags and a pulse back-blowing device. Preferably, the dust removal filter bags are made of a new type of high-efficiency filter bags made of all PDFE material, with an instantaneous temperature resistance of 280 °C, a long-term working temperature of up to 260 °C, and are wear-resistant, corrosion-resistant and durable.

[0029] In an embodiment, the catalytic denitration system includes a denitration reactor 9. The inlet flue 8 and the outlet flue 28 are arranged at both ends of the denitration reactor 9. The third expansion joint 26 and the fourth expansion joint 27 are respectively arranged on the inlet flue 8 and the outlet flue 28. The denitration reactor 9 is provided with a flow equalizer 10 and a denitration catalyst 11. The flow equalizer 10 is arranged at the rear end in the flue gas traveling direction, and the denitration catalyst 11 is arranged at the front end in the flue gas traveling direction.

[0030] Preferably, third transmitters 30 and fourth transmitters 31 are respectively arranged on the inlet flue 8 and the outlet flue 28 to monitor the temperatures of the flue gas at the inlet and outlet of the denitration reactor 9 to avoid damage to the catalyst. The denitration reactor 9 is provided with a sonic soot blower 22. The denitration catalyst 11 is arranged in at least three layers. The sonic soot blower 22 is used to blow soot on each layer of the denitration catalyst 11. The sonic soot blower 22 is connected to a compressed air supply system 23 through a pipeline and a valve 21. More preferably, the denitration catalyst 11 is a medium and low temperature vanadium-based honeycomb catalyst with a model of 30 holes or more. Three layers are arranged. When the efficiency decreases after running for a certain period of time or when the catalyst layers are rotated and replaced, the remaining layer is additionally installed. Since the flue gas has been dust-removed and the dust concentration is very low, there is no need to use a pneumatic rake-type soot blower, and only a simple sonic soot blower 22 is required.

[0031] An ammonia injection grid 20 is provided on the inlet flue 8. The ammonia injection grid 20 is located at the rear end of the inlet direction of the third expansion joint 26. The ammonia injection grid 20 is connected to the reductant supply system 15. The reductant supply system 15 includes a preparation device, an ammonia-air mixing device 16 and a corrugated pipe 19. The preparation device is connected to the ammonia-air mixing device 16. The ammonia-air mixing device 16 is connected to the ammonia injection grid 20 through a pipeline. A regulating valve 17, a flowmeter 18 and a corrugated pipe 19 are provided on the pipeline. At least 3 groups of ammonia injection grids 20 are provided; preferably, the preparation device is used to prepare any one of the process devices such as ammonia production by ammonia water gasification, ammonia production by liquid ammonia evaporation, ammonia production by urea solution hydrolysis or ammonia production by urea solution pyrolysis. In this embodiment, ammonia production by urea solution hydrolysis is adopted.

[0032] In the embodiment, the outlet flue 28 is connected to the subsequent flue gas treatment system 12 through a pipeline. A branch is provided on the pipeline. A dilution fan 13 and a dilution damper 14 are provided on the branch. The dilution damper 14 is arranged at the outlet end of the dilution fan 13. The dilution damper 14 is connected to the ammonia-air mixing device 16 through a pipeline.

[0033] The utility model stabilizes the flue gas temperature of the high-temperature flue gas within the specified required value through three-stage temperature control measures and then enters the bag filter 7 to ensure that the bag is not damaged and the dust removal effect is ensured; through cooling and a long residence time, hydrogen fluoride in the flue gas can form solid substances such as calcium fluoride and magnesium fluoride. It can be trapped by the dust collector. The dust collector can also trap salts such as alkali metals or alkaline earth metals in the flue gas; the poisoning effect of these harmful components on the denitration catalyst 11 is eliminated, ensuring that the denitration catalyst 11 is not damaged, so as to achieve long-term stable operation; a special medium and low temperature high-efficiency denitration catalyst 11 is adopted and arranged in multiple layers to ensure high denitration efficiency.

[0034] In the second embodiment, the furnace temperature of the smelting furnace is different under different working conditions and time periods, and the flue gas temperature is also different. The flue gas temperature is low during the smelting start period and the discharging period after smelting ends, and the flue gas temperature is high during the intermediate high-temperature smelting period. The flue gas (about 400 °C) in the low-temperature period passes through the coil type surface cooler 2, and the flue gas temperature drops to about 240 °C and then enters the dust collector. After dust removal, the flue gas temperature will also drop to about 220 °C due to heat dissipation, and then enters the medium and low temperature catalytic denitration reactor 9. After passing through three layers of denitration catalysts 11, NOx in the flue gas and the denitration reductant NH3 carry out a selective catalytic reduction reaction to generate nitrogen and water. After denitration, the flue gas temperature also drops to about 200 °C and continues to enter other subsequent treatment facilities, and finally reaches the standard for discharge. After operating for a period of time, the sonic soot blower 22 is controlled to be turned on according to the pressure difference between the front and rear of the catalyst to loosen the dust attached to the surface of the catalyst so that it can be blown away by the airflow to prevent blockage formed by accumulation on the surface.

[0035] Example 3: During the smelting period, the flue gas temperature is about 800 °C. After passing through the surface cooler 2, the flue gas temperature can be reduced to below 400 °C, but it is still higher than the temperature that the dust collector can tolerate. At this time, turn on the water sprayer 3 and perform the linkage adjustment of the water spray regulating valve 17 and the first transmitter 24. When the flue gas temperature is high, open the water valve wider; when the flue gas temperature is low, close the regulating valve 17 slightly, so as to control the flue gas temperature to enter the subsequent treatment facilities at about 240 °C, and realize the normal operation of the dust removal and denitration devices. The operation conditions of the subsequent facilities are the same as those in Example 1.

[0036] Example 4: When the kiln furnace condition is abnormal and the flue gas temperature leaving the furnace is higher than 800 °C or even above 1000 °C, after passing through the surface cooler 2, the flue gas temperature will still be higher than 400 °C, and the flue gas temperature cannot be reduced to below 260 °C after turning on the water spray; or when the water spray system fails or the water supply is cut off and the flue gas temperature exceeds 260 °C, at this time, turn on the cold air system 4 and perform the combined adjustment of the cold air regulating valve 17 and the second transmitter 29 to ensure that the flue gas temperature is about 240 °C and enters the subsequent treatment facilities, so as to ensure the normal operation of the subsequent dust collector and denitration devices. The subsequent treatment facilities are the same as those in Example 1.

[0037] The above are the preferred embodiments of the present invention and the technical principles applied. For those skilled in the art, any obvious changes such as equivalent transformation and simple substitution based on the technical solution of the present invention without departing from the spirit and scope of the present invention shall fall within the protection scope of the present invention.

Claims

1. A flue gas denitration device for an enamel material production line, comprising a flue gas temperature control system, a dust removal pretreatment system, a catalytic denitration system and a reducing agent supply system connected by pipelines, characterized in that: The flue gas temperature control system is connected to the flue gas inlet through a pipeline. The flue gas temperature control system includes a coil surface cooler, a water sprayer, a cold air system, and a temperature transmitter arranged on the pipeline. The temperature transmitter includes a first transmitter and a second transmitter, which are respectively arranged at the front end of the water sprayer and the cold air system in the flue gas traveling direction, and are used to monitor the flue gas temperature and adjust the cooling operations of the water sprayer and the cold air system.

2. The flue gas denitrification equipment for the enamel material production line according to claim 1, characterized in that: The surface cooler is a folded flue duct assembly made of thin steel plates.

3. The flue gas denitrification equipment for the enamel material production line according to claim 1, characterized in that: The water sprayer includes a spray water pipe, a regulating valve, and a nozzle. The regulating valve is linked and controlled with the first transmitter. When the flue gas temperature is high, the valve opening is increased; when the flue gas temperature is low, the valve is closed or its opening is reduced.

4. The flue gas denitration equipment for the enamel material production line according to claim 1, characterized in that: The cold air system includes a cold air pipe, a cold air valve, a flue duct mixer, and a second transmitter. The cold air valve is arranged on the cold air pipe, the cold air pipe is connected to the flue duct mixer, and the second transmitter is arranged at the front end of the flue duct mixer; the cold air valve is normally fully closed. When the first transmitter detects abnormal flue gas temperature, the cold air valve is fully opened to prevent the dust removal pretreatment system from being damaged by sudden high temperature. The cold air valve is adjusted according to the detection result of the second transmitter to control the flue gas temperature within the required range.

5. The flue gas denitration equipment for the enamel material production line according to claim 1, characterized in that: The dust removal pretreatment system includes a first expansion joint, a dust collector box body, and a second expansion joint. The first expansion joint and the second expansion joint are respectively arranged at the inlet and outlet of the dust collector box body. The dust collector box body is provided with dust removal filter bags and a pulse backwashing device.

6. The flue gas denitrification equipment for the enamel material production line according to claim 1, characterized in that: The catalytic denitration system includes a denitration reactor. Inlet flue ducts and outlet flue ducts are arranged at both ends of the denitration reactor. A third expansion joint and a fourth expansion joint are respectively arranged on the inlet flue duct and the outlet flue duct. A flow equalizer and denitration catalyst are arranged in the denitration reactor. The flow equalizer is arranged at the rear end in the flue gas traveling direction, and the denitration catalyst is arranged at the front end in the flue gas traveling direction.

7. The flue gas denitration equipment for the enamel material production line according to claim 6, characterized in that: An acoustic soot blower is arranged on the denitration reactor. The denitration catalyst is arranged in at least three layers, and the acoustic soot blower is used to blow soot on each layer of the denitration catalyst.

8. The flue gas denitrification equipment for the enamel material production line according to claim 6, characterized in that: A spray ammonia grid is arranged on the inlet flue duct, which is located at the rear end of the intake direction of the third expansion joint. The spray ammonia grid is connected to the reducing agent supply system.

9. The flue gas denitration equipment for the enamel material production line according to claim 1, characterized in that: The reducing agent supply system includes a preparation device, an ammonia-air mixing device, and a corrugated pipe. The preparation device is connected to the ammonia-air mixing device. The ammonia-air mixing device is connected to the spray ammonia grid through a pipeline. A regulating valve, a flowmeter, and a corrugated pipe are arranged on the pipeline. At least 3 groups of spray ammonia grids are arranged.

10. The flue gas denitrification equipment for the enamel material production line according to claim 6, characterized in that: The outlet flue duct is connected to the subsequent flue gas treatment system through a pipeline. A branch is arranged on the pipeline. A dilution blower and a dilution damper are arranged on the branch. The dilution damper is arranged at the outlet end of the dilution blower. The dilution damper is connected to the ammonia-air mixing device through a pipeline.

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