Vertical SCR (Selective Catalytic Reduction) offline regeneration system with heating function

Abstract

The utility model discloses a vertical SCR (Selective Catalytic Reduction) offline regeneration system with a heating function, which is characterized in that electric heating pipes are additionally arranged around an inner cavity of a vertical regeneration reactor and between catalyst bed layers, so that the temperature difference between an air inlet and an air outlet in the regeneration process can be reduced, and the temperature in the reactor is as uniform as possible; the heating power of the electric heater is adjusted according to the temperature conditions of different partitions by adopting a partition temperature adjusting mode, so that the temperatures of the different partitions are close to a set temperature value, the purpose of uniform overall temperature in the reactor is realized, and the thorough decomposition of ammonium sulfate salt and the regeneration effect of a catalyst are ensured; the vertical regeneration reactor solves the problems of non-uniform temperature in the regeneration reactor, large temperature difference of flue gas at an inlet and an outlet, non-ideal regeneration effect and poor denitration efficiency of a regenerated catalyst in the traditional vertical regeneration technology.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of catalyst regeneration, specifically relates to a vertical SCR off-line regeneration system with heating. BACKGROUND

[0002] The emission index of atmospheric pollutants in the industries such as thermal power, steel, cement and waste incineration is becoming increasingly strict, and for the standard emission of nitrogen oxides, the current SCR technology is the most stable, efficient and reliable nitrogen oxide control technology. The catalyst, as the core of the SCR technology, plays a decisive role in the investment operation cost and operation stability of the SCR technology. The SCR catalyst can accelerate the reaction rate and improve the selectivity of the reaction in the chemical reaction. However, with the increase of the use time, the catalyst may be affected by the dust scouring and poisoning, thereby affecting the activity and selectivity of the catalyst and leading to the deactivation.

[0003] In the waste incineration power plant flue gas purification process, SNCR denitration + semi-dry method deacidification + activated carbon adsorption + dry method deacidification + bag dust removal + SCR denitration are usually adopted, wherein the SCR adopts a low-temperature catalyst, and the operation temperature is 170-230 DEG C. In this temperature range, NH3 in the flue gas is easy to react with SO2 and SO3 in the flue gas to generate ammonium bisulfate and ammonium bisulfite, which are adhered to the surface of the catalyst, block the pore structure of the catalyst, cover the surface active sites, hinder the adsorption and reaction of NO x And the reducing agent NH3 on the surface active sites of the catalyst, thereby leading to the deactivation of the catalyst. The deactivated catalyst needs to be recovered in activity through heat regeneration before being used continuously.

[0004] At present, the vertical in-situ regeneration technology and the vertical off-site regeneration technology commonly used in the waste incineration power plant have the problems of uneven temperature distribution of the catalyst in the regeneration process due to the large volume of the regeneration reactor and the insufficient sealing and heat preservation of the regeneration system, thereby leading to the incomplete decomposition of ammonium sulfate salt or the sintering of the catalyst, affecting the activity of the catalyst after heat regeneration and leading to the unsatisfactory denitration effect of the regenerated catalyst.

[0005] On this basis, a vertical SCR off-line regeneration system with heating is provided. UTILITY MODEL CONTENTS

[0006] The technical problem solved by the utility model is that the vertical SCR off-line regeneration system with heating can solve the problem of poor catalyst regeneration effect caused by the too large temperature difference between the inlet and outlet of the hot flue gas of the existing vertical regeneration device.

[0007] Technical Solution: A heated vertical SCR offline regeneration system includes a vertical regeneration reactor. A catalyst module is located in the middle of the vertical regeneration reactor. The catalyst module includes an upper catalyst module and a lower catalyst module. Electric heating tubes are installed around the catalyst module and between the upper and lower catalyst modules. A temperature detector for different catalyst bed layers and a pressure gauge for the regeneration reactor are installed between the upper and lower catalyst modules. A flue gas temperature detector for the inlet of the regeneration reactor is located at the top of the vertical regeneration reactor, and a flue gas temperature detector for the outlet of the regeneration reactor is located at the bottom of the vertical regeneration reactor. A regeneration air circulation fan and a regeneration air electric heater are sequentially connected to the main pipe connecting the flue gas outlet and the flue gas inlet of the vertical regeneration reactor. A flue gas temperature detector for the inlet of the regeneration air electric heater is installed at the inlet end of the pipe, and a regeneration circulation air flow meter is installed at the outlet end of the pipe.

[0008] Preferably, the regeneration system further includes an exhaust system and a makeup air system. The main duct has two openings on its side wall. The first opening is connected to the air inlet of the exhaust system through a first duct, and the second opening is connected to the air outlet of the makeup air system through a second duct.

[0009] Furthermore, the exhaust system includes an exhaust system electric regulating valve, an electric heating tape, and an exhaust fan arranged sequentially on the first pipe. The first pipe inside the electric heating tape is equipped with an exhaust air flow meter, and the outlet of the first pipe is connected to the inlet of the semi-dry reaction tower.

[0010] Furthermore, the make-up air system includes an electric regulating valve for the make-up air system installed on the second pipe, and a make-up air flow meter is installed in the second pipe between the second opening and the electric regulating valve for the make-up air system. The air source of the make-up air system is fresh air.

[0011] Furthermore, both the regenerated air circulation fan and the exhaust fan are variable frequency fans.

[0012] Preferably, a detection port is provided on the duct at the air inlet of the regenerated air circulating fan.

[0013] Beneficial effects: By installing electric heating tubes around the inner cavity of the vertical regeneration reactor and between the catalyst bed, the regeneration system of this utility model can reduce the temperature difference between the inlet and outlet during the regeneration process, making the temperature inside the reactor as uniform as possible.

[0014] By adopting a zoned temperature regulation method, the heating power of the electric heater is adjusted according to the temperature conditions of different zones, so that the temperature of different zones approaches the set temperature value, thereby achieving the goal of uniform overall temperature in the reactor, ensuring the complete decomposition of ammonium sulfate and the regeneration effect of the catalyst.

[0015] This invention solves the problems of uneven temperature inside the regeneration reactor, large temperature difference between inlet and outlet flue gas, unsatisfactory regeneration effect, and poor denitrification efficiency of the catalyst after regeneration in traditional vertical regeneration technology (online and offline). Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a vertical SCR offline regeneration system with heating according to this utility model;

[0017] The numbers in the diagram are as follows: 1. Vertical regeneration reactor; 2. Catalyst module; 3. Electric heating tube; 4. Regeneration air electric heater; 5. Regeneration air circulating fan; 6. Regeneration circulating air flow meter; 7. Exhaust system electric regulating valve; 8. Exhaust air flow meter; 9. Exhaust fan; 10. Electric heating tape; 11. Makeup air flow meter; 12. Makeup air system electric regulating valve; 13. Electric heater inlet flue gas temperature detector; 14. Regeneration reactor inlet flue gas temperature detector; 15. Catalyst bed temperature detector; 16. Regeneration reactor outlet flue gas temperature detector; 17. Regeneration reactor pressure gauge; 18. Detection port; 19. Makeup air system; 20. Exhaust system. Detailed Implementation

[0018] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings. Example

[0019] Reference Figure 1 A heated vertical SCR offline regeneration system includes a vertical regeneration reactor 1. A catalyst module 2 is located in the middle of the vertical regeneration reactor 1. The catalyst module 2 includes an upper catalyst module and a lower catalyst module. Electric heating tubes 3 are installed around the catalyst module and between the upper and lower catalyst modules. A catalyst bed temperature detector 15 and a regeneration reactor pressure gauge 17 are installed between the upper and lower catalyst modules. A regeneration reactor inlet flue gas temperature detector 14 is installed at the upper part of the vertical regeneration reactor 1, and a regeneration reactor outlet flue gas temperature detector 16 is installed at the lower part of the vertical regeneration reactor 1. A regeneration air circulation fan 5 and a regeneration air electric heater 4 are sequentially connected to the main pipe connecting the flue gas outlet and flue gas inlet of the vertical regeneration reactor 1. An electric heater inlet flue gas temperature detector 13 is installed at the inlet end pipe of the regeneration air electric heater 4, and a regeneration circulation air flow meter 6 is installed at the outlet end pipe of the regeneration air electric heater 4.

[0020] The heated vertical SCR offline regeneration system also includes an exhaust system 20 and a makeup air system 19. Two openings are formed on the side wall of the main duct. The first opening connects to the air inlet of the exhaust system 20 via a first duct, and the second opening connects to the air outlet of the makeup air system via a second duct. The exhaust system 20 includes an electric regulating valve 7, an electric heating tape 10, and an exhaust fan 9, sequentially arranged on the first duct. An exhaust air flow meter 8 is installed in the first duct within the electric heating tape 10. The air outlet of the first duct is connected to the inlet of the semi-dry reaction tower. The makeup air system 19 includes an electric regulating valve 12 installed on the second duct. A makeup air flow meter 11 is installed in the second duct between the second opening and the electric regulating valve 12. The air source for the makeup air system 19 is fresh air.

[0021] An inspection port 18 is provided on the duct at the air inlet of the aforementioned regenerated air circulating fan 5.

[0022] In operation, the catalyst modules 2 are first hoisted into the vertical regeneration reactor 1 in sequence. After all catalyst modules 2 are in place, the regeneration system is started. The electric regulating valve 12 of the make-up air system and the electric regulating valve 7 of the exhaust system are closed, and the regeneration air electric heater 4 and the regeneration air circulating fan 5 are turned on.

[0023] The regeneration air circulation fan 5 is a variable frequency fan, and the air volume is adjusted by changing the frequency. The frequency of the regeneration air circulation fan 5 is adjusted according to the flow rate feedback from the regeneration circulation air volume meter 6 at the inlet of the vertical regeneration reactor 1, thereby achieving the set regeneration circulation air volume.

[0024] The regenerated circulating air is heated from room temperature to a specified temperature after passing through the regenerated air electric heater 4. The heated regenerated air enters the vertical regeneration reactor 1, where it exchanges heat with the catalyst module 2 and its temperature decreases. Under the action of the regenerated air circulation fan 5, it passes through the regenerated air electric heater 4 again to be heated and enters the vertical regeneration reactor 1 to exchange heat with the catalyst module 2, realizing the regenerated air circulation until both the regenerated air and the catalyst module 2 reach the specified temperature. The power of the regenerated air electric heater 4 is adjusted according to the temperature fed back by the electric heater inlet flue gas temperature detector 13 and the set target temperature.

[0025] When the temperature of the regeneration air and catalyst module 2 reaches above 300℃, ammonium sulfate begins to decompose in large quantities. Based on the pressure value read by the pressure gauge 17 of the regeneration reactor (which should be positive pressure at this time and gradually increase with the increase of temperature), the electric regulating valve 7 of the exhaust system and the exhaust fan 9 are turned on. The exhaust fan 9 is a variable frequency fan, and the exhaust air volume is achieved by adjusting the fan frequency. The frequency of the exhaust fan 9 is controlled according to the exhaust air flow rate read by the exhaust air flow meter 8 and the set exhaust air volume, so that the vertical regeneration reactor 1 is kept under a slight negative pressure through exhaust.

[0026] The temperature of the regeneration air and catalyst module 2 is continuously increased until it stabilizes at 400℃, and ammonium sulfate continues to decompose in large quantities. At this time, the electric regulating valve 7 of the exhaust system is fully open, and the exhaust fan 9 is set to the rated value. The electric regulating valve 12 of the makeup air system is fully open, and the makeup air volume is equivalent to the exhaust air volume. Due to the large volume of the vertical regeneration reactor 1, the temperature drop will occur due to heat exchange and heat dissipation losses when the regeneration air enters the vertical regeneration reactor 1. Several temperature measuring points are set in sections around the catalyst module 2 and between the two layers of catalyst modules 2. Based on the temperature feedback from the temperature detector 15 between different catalyst bed layers and the flue gas temperature detector 16 at the outlet of the regeneration reactor, the heating power of the electric heating tube 3 is adjusted accordingly to ensure a uniform temperature distribution inside the vertical regeneration reactor 1, reduce the temperature difference between the inlet and outlet, and thus ensure that the ammonium sulfate on the surface of the catalyst modules in different layers and positions can be completely decomposed at 400℃.

[0027] The temperature of the regeneration air and catalyst module 2 is stabilized at around 400℃. The regeneration waste gas containing SO2, HCl, and NH3 is discharged into the semi-dry reaction tower for tail gas treatment via exhaust system 20 under the action of exhaust fan 9. The concentrations of SO2 and NH3 in the regeneration waste gas are detected through detection port 18. The regeneration decomposition process ends when the concentrations reach the standard. The duration of the regeneration decomposition stage depends on whether the SO2 and NH3 concentrations in the regeneration waste gas meet the standard.

[0028] After the regeneration and decomposition stage is completed, the regeneration air heater 4 is turned off, while the regeneration air circulation fan 5 and exhaust fan 9 remain on, maintaining a constant exhaust air volume. The electric regulating valve 12 of the make-up air system is fully open, and the introduction of cold air causes the overall temperature of the vertical regeneration reactor 1 to steadily decrease. When the overall temperature of the vertical regeneration reactor 1 drops to a suitable level, the regeneration air circulation fan 5, exhaust fan 9, exhaust system electric regulating valve 7, and make-up air system electric regulating valve 12 are turned off, allowing the vertical regeneration reactor 1 to cool naturally. After cooling to room temperature, the catalyst module 2 is hoisted out of the vertical regeneration reactor 1, and the entire regeneration process is complete.

[0029] The embodiments described herein are preferred embodiments of this utility model and are not intended to limit the scope of protection of this utility model. Therefore, all equivalent changes made to the structure, shape, and principle of this utility model should be included within the scope of protection of this utility model.

Claims

1. A heated vertical SCR off-line regeneration system characterized by: The vertical regeneration reactor (1) is provided with a catalyst module (2) in the middle part, the catalyst module (2) comprises an upper catalyst module and a lower catalyst module, an electric heating pipe (3) is arranged around the catalyst module and between the upper catalyst module and the lower catalyst module, a catalyst different bed temperature detector (15) and a regeneration reactor pressure gauge (17) are arranged between the upper catalyst module and the lower catalyst module, a regeneration reactor inlet flue gas temperature detector (14) is arranged at the upper part of the vertical regeneration reactor (1), a regeneration reactor outlet flue gas temperature detector (16) is arranged at the lower part of the vertical regeneration reactor (1), a regeneration air circulating fan (5) and a regeneration air electric heater (4) are sequentially connected on the main pipeline connected with the flue gas inlet and the flue gas outlet of the vertical regeneration reactor (1), an electric heater inlet flue gas temperature detector (13) is arranged on the inlet end pipeline of the regeneration air electric heater (4), and a regeneration circulating air volume flow meter (6) is arranged on the outlet end pipeline of the regeneration air electric heater (4).

2. A vertical SCR off-line regenerative system with heating according to claim 1, characterized in that: The exhaust system (20) and the air supplement system (19) are further included, two openings are arranged on the side wall of the main pipeline, a first opening is connected with the air inlet of the exhaust system (20) through a first pipeline, and a second opening is connected with the air outlet of the air supplement system through a second pipeline.

3. A vertically mounted SCR off-line regenerative system with heating according to claim 2, characterized in that: The exhaust system (20) comprises an exhaust system electric regulating valve (7), an electric heating belt (10) and an exhaust fan (9) arranged on the first pipeline in sequence, the first pipeline in the electric heating belt (10) is provided with an exhaust air volume flow meter (8), and the air outlet of the first pipeline is connected with the inlet of the semi-dry reaction tower.

4. A vertical SCR off-line regenerative system with heating according to claim 2, characterized in that: The air supplement system (19) comprises an air supplement system electric regulating valve (12) arranged on the second pipeline, the second pipeline between the second opening and the air supplement system electric regulating valve (12) is provided with an air supplement air volume flow meter (11), and the air source of the air supplement system (19) is fresh air.

5. A vertical SCR off-line regenerative system with heating according to claim 2, characterized in that: The regeneration air circulating fan (5) and the exhaust fan (9) are variable frequency fans.

6. A vertically mounted off-line SCR regenerative system with heating according to claim 1, characterized in that: A detection opening (18) is arranged on the pipeline of the air inlet of the regeneration air circulating fan (5).

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