An integrated flue gas purification device that can be used for desulfurization, dust removal, and denitrification of high-temperature flue gas.

Abstract

This utility model belongs to the field of high-temperature flue gas desulfurization, denitrification, and dust removal technology, and specifically relates to an integrated flue gas purification device that can be used for high-temperature flue gas desulfurization, dust removal, and denitrification. It includes an inlet duct and valve assembly and an outlet duct and valve assembly, which are respectively fixed to the upper and lower ends of the device body. Inside the device body, from top to bottom, are arranged a high-temperature denitrification catalyst, a high-temperature metal compensator, a backflushing cleaning device, and a high-temperature resistant metal filter bag. Integrating desulfurization, dust removal, and denitrification into a single device offers advantages such as multiple flue gas purification functions, high integration, small footprint, and low investment.

Description

Technical Field

[0001] This utility model belongs to the field of high-temperature flue gas desulfurization, denitrification and dust removal technology, and specifically relates to an integrated flue gas purification device that can be used for high-temperature flue gas desulfurization, dust removal and denitrification. Background Technology

[0002] Traditional flue gas desulfurization, denitrification, and dust removal processes require baghouse dust collectors to meet ultra-low particulate matter emission requirements. However, the filter bags made of synthetic fibers or glass fibers can only withstand temperatures up to 260℃–280℃ for extended periods. Prolonged operation near these maximum temperatures significantly shortens the bag's lifespan. Therefore, high-temperature flue gas typically requires cooling before desulfurization, dust removal, and low-temperature denitrification. If a process of high-temperature denitrification followed by desulfurization and dust removal is adopted, a large amount of dust in the flue gas will adhere to and gradually clog the pores of the denitrification catalyst. SO2 in the flue gas reacts with the SCR catalyst to form sulfate deposits, blocking the active sites on the catalyst surface and reducing its catalytic activity. This leads to a decrease in the denitrification efficiency of the SCR system and an increase in nitrogen oxide (NOx) emissions. Furthermore, the accumulation of sulfate deposits also reduces the catalyst's lifespan and increases maintenance costs. The new integrated dust, nitrogen, and sulfur purification technology using ceramic filter cartridges replaces traditional filter bags. Ceramic filter cartridges are resistant to high temperatures and corrosion, making them suitable for high-temperature flue gas filtration and meeting the desulfurization and dust removal requirements before high-temperature denitrification. However, ceramic filter cartridges are relatively brittle, with a maximum length of only 3 meters. This results in dust collectors using filter cartridges either having a large footprint or requiring a two-layer layout, leading to increased investment in steel structures and ash conveying systems.

[0003] With the maturation of the new generation of high-temperature resistant metal filter bags, it is now possible to desulfurize, remove dust, and then denitrify high-temperature flue gas. The high-temperature resistant metal filter bags are also very close to traditional filter bags in terms of parameters such as filtration velocity, filter bag diameter, and length.

[0004] In conclusion, an integrated flue gas purification device capable of achieving ultra-low emissions of nitrogen oxides, SO2, and particulate matter from high-temperature flue gas, which can be used for desulfurization, dust removal, and denitrification of high-temperature flue gas, is technically feasible and essential for further reducing the cost of high-temperature flue gas purification. Utility Model Content

[0005] This invention relates to an integrated flue gas purification device that can be used for desulfurization, dust removal, and denitrification of high-temperature flue gas, in order to solve the technical problem of requiring ultra-low emissions of sulfur dioxide, particulate matter, and nitrogen oxides when using dry purification processes for organized high-temperature flue gas in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: An integrated flue gas purification device for high-temperature flue gas desulfurization, dust removal, and denitrification includes an inlet pipe and valve assembly and an outlet pipe and valve assembly, which are respectively fixed to the upper and lower ends of the device body. The interior of the device body is arranged from top to bottom as follows: a high-temperature denitrification catalyst, a high-temperature metal compensator, a backflushing cleaning device, and a high-temperature resistant metal filter bag.

[0007] The device body is a cylindrical shell with an inverted cone at the top. The larger diameter end of the cone is connected and fixed to the upper end of the device body. The smaller diameter end of the cone is connected to a tubular end cap via a flange. The outer end of the end cap is connected to an air outlet valve assembly. The air outlet valve assembly is responsible for discharging the purified gas from the device. The valves are pneumatic.

[0008] The lower part of the device body is a dust collector hopper with a conical tube body. One side of the dust collector hopper is connected to an air inlet pipe and a valve assembly. The air inlet pipe and valve assembly are responsible for introducing dust-laden flue gas into the device. The valves are either manual or pneumatic.

[0009] The upper part of the device body is the catalytic section, which is equipped with a high-temperature denitrification catalyst. The device body is equipped with a support grid, and the high-temperature denitrification catalyst is placed on the support grid.

[0010] The high-temperature denitrification catalyst is made of vanadium-titanium and tungsten-titanium materials, and its applicable temperature is 300℃~400℃.

[0011] The high-temperature denitrification catalyst is equipped with a purification device at the lower end, and a high-temperature resistant metal compensator is provided in the middle and upper part of the purification device. The high-temperature resistant metal compensator is made of stainless steel and can withstand temperatures up to 450℃. The diameter of the high-temperature resistant metal compensator is 2~5m, and its pressure resistance meets 0.1MPa.

[0012] The lower part of the high-temperature resistant metal compensator is the desulfurization and dust removal section. The lower end of the desulfurization and dust removal section is equipped with a reverse-flushing cleaning device, which adopts a row jet cleaning arrangement.

[0013] The lower end of the reverse-flushing dust removal device is equipped with a high-temperature resistant metal filter bag, and the inside of the device body is provided with perforated plate. The high-temperature resistant metal filter bag is fixed to each perforated plate hole on the inner wall of the device body through a sealing flange.

[0014] The high-temperature resistant metal filter bag is made by pressing stainless steel metal powder and then sintering it. The longitudinal spacing of the high-temperature resistant metal filter bag is 200mm~250mm, the transverse spacing is 200mm~250mm, and the temperature resistance range of the high-temperature resistant metal filter bag is 450℃~600℃.

[0015] The lower end of the device body 2 is a dust collector hopper with a conical tube body, and the angle of the conical hopper is between 60° and 70°.

[0016] Compared with the prior art, the present invention has the following beneficial effects: Compared to flue gas treatment processes using traditional synthetic fiber filter bags, stainless steel metal filter bags can operate at higher temperatures and utilize high-temperature denitrification catalysts, offering advantages such as higher denitrification efficiency and lower procurement costs. Furthermore, this integrated flue gas purification device features a high degree of integration of desulfurization, dust removal, and denitrification, a smaller footprint, and a lower overall investment compared to traditional synthetic fiber filter bag dust removal and desulfurization + SCR low-temperature denitrification systems. The flue gas after desulfurization and dust removal minimizes the adverse effects on the denitrification catalyst, extending its service life.

[0017] This invention proposes an integrated flue gas purification device for high-temperature flue gas desulfurization, dust removal, and denitrification. It integrates these three flue gas purification functions into a single device, offering advantages such as multiple purification functions, high integration, small footprint, and low investment. The device utilizes stainless steel filter bags with a maximum temperature resistance of 450℃~600℃, offering high filtration accuracy, good air permeability, and low resistance. The stainless steel substrate provides excellent corrosion resistance, allowing alkaline desulfurizing agents to adhere to the filter bag surface. The low flue gas velocity at the filter bag surface further enhances desulfurization efficiency. With the stainless steel filter bags, the device can operate normally between 300℃ and 400℃. This temperature range is optimal for the active dry-process calcium hydroxide desulfurizing agent and the high-temperature denitrification catalyst, ensuring that desulfurization, dust removal, and denitrification all meet standards within a single purification unit. A high-temperature metal compensator serves as the connecting link between the stainless steel filter bag section and the denitrification catalyst section, allowing the two heavily loaded functional sections to be fixed to the steel structure frame, preventing excessively high center of gravity and high steel structure investment. High-temperature metal compensators effectively absorb the thermal expansion of the casing, facilitating the use of filter bags longer than 6 meters and increasing the flue gas treatment capacity of the system within a given cross-sectional area. The inlet and outlet ducts are equipped with manual or pneumatic valves, allowing multiple units to be connected in parallel to form a large flue gas purification system, increasing treatment capacity. Alternatively, a single unit can be disconnected from the system for independent backflushing and cleaning, improving cleaning efficiency. The backflushing system uses compressed air or compressed nitrogen (when the flue gas is flammable or explosive) as the backflushing gas source. Attached Figure Description

[0018] Figure 1 : A schematic diagram of an integrated flue gas purification device that can be used for desulfurization, dust removal and denitrification of high-temperature flue gas.

[0019] Labeling Explanation: 1. Inlet duct and valve assembly; 2. Unit body; 3. High-temperature denitrification catalyst; 4. High-temperature metal compensator; 5. Backflushing cleaning device; 6. High-temperature resistant metal filter bag; 7. Outlet duct and valve assembly. Detailed Implementation

[0020] To further understand the present invention, the following detailed description is provided in conjunction with the accompanying drawings and specific embodiments. It should be understood that the embodiments are merely illustrative and not intended to limit the scope of the invention.

[0021] To further illustrate the technical means and effects of this utility model in achieving its intended purpose, the specific implementation methods, structural features and effects of this utility model are described in detail below with reference to the accompanying drawings and embodiments.

[0022] like Figure 1 As shown, this utility model provides an integrated flue gas purification device that can be used for high-temperature flue gas desulfurization, dust removal, and denitrification, such as... Figure 1 As shown, the device includes an inlet duct and valve assembly 1, a main body 2, a high-temperature denitrification catalyst 3, a high-temperature metal compensator 4, a backflushing cleaning device 5, 6 high-temperature resistant metal filter bags, and an outlet duct and valve assembly 7. The main body 2 is a cylindrical shell with an inverted conical hopper at its upper end. The larger diameter end of the conical hopper is connected and fixed to the upper end of the main body 2, while the smaller diameter end of the conical hopper is connected to a tubular end cap via a flange. The outer end of the end cap is connected to the outlet duct and valve assembly 7. The lower part of the main body 2 is a conical dust collector hopper, with the inlet duct and valve assembly 1 connected to one side of the hopper. The inlet duct and valve assembly 1 is responsible for introducing dust-laden flue gas into the device, and the valves are either manual or pneumatic. The outlet duct and valve assembly 7 is responsible for discharging purified gas. The valves are typically pneumatic; during cleaning, closing the valves prevents negative pressure from the fan from reaching the device, improving the backflushing cleaning efficiency. The upper part of the device body 2 is equipped with a high-temperature denitrification catalyst 3. A supporting grid is located inside the device body 2, and the high-temperature denitrification catalyst 3 is placed on the supporting grid. The high-temperature denitrification catalyst 3 is made of materials such as vanadium-titanium and tungsten-titanium, and is suitable for temperatures between 300℃ and 400℃, where the denitrification efficiency is highest. The loading amount of the high-temperature denitrification catalyst 3 is adjusted according to the nitrogen oxide concentration and flue gas volume. The flue gas entering the high-temperature denitrification catalyst 3 stage has already undergone desulfurization and dust removal, effectively preventing dust blockage of the catalyst and SO2 poisoning. A purification device is located at the lower end of the high-temperature denitrification catalyst 3. A high-temperature resistant metal compensator 4 is located in the upper middle part of the purification device. The lower end of the high-temperature resistant metal compensator 4 is the desulfurization and dust removal section. The high-temperature resistant metal compensator 4 connects the upper denitrification section and the lower desulfurization and dust removal section, compensating for the thermal expansion of the purification device body under high-temperature operation. The high-temperature resistant metal compensator 4 is made of stainless steel to ensure sufficient thermal strength at high temperatures.

[0023] The high-temperature resistant metal compensator 4 is made of 304 or 316 stainless steel and can withstand temperatures up to 450℃. When using 310S, it can withstand temperatures up to 800℃. The compensator has a diameter of 2~5m and a pressure resistance of 0.1MPa. The desulfurization and dust removal section at the lower part of the high-temperature resistant metal compensator 4 is equipped with a back-flushing cleaning device 5 at its lower end. A high-temperature resistant metal filter bag 6 is located at the lower end of the back-flushing cleaning device 5. The high-temperature resistant metal filter bags 6 are arranged in multiple vertical rows, each row containing several high-temperature resistant metal filter bags 6. The back-flushing cleaning device 5 adopts a row-jet cleaning arrangement, and each row of high-temperature resistant metal filter bags 6 is equipped with an independent back-flushing cleaning device 5. The high-temperature resistant metal filter bag 6 is made of stainless steel powder or stainless steel wire mesh, which is formed by pressing and sintering. It is a mature filter material available on the market. When the operating temperature is less than 400℃, 304 and 316L materials can be selected. 304 material has good temperature resistance, while 316L material has better corrosion resistance in addition to good temperature resistance. When the operating temperature is between 400-600℃, 310S and 314 materials can be selected, which have high-temperature oxidation resistance. When the temperature is greater than 600℃, iron-chromium-aluminum material can be selected. Other materials such as Hastelloy and nickel are also available as needed. It features high temperature resistance, corrosion resistance, high strength, good wear resistance, good air permeability for easy dust removal, good conductivity without static electricity, and long service life. The backflushing dust removal device 5 mainly consists of a gas storage tank, a gas distribution box, backflushing pipes, and pulse valves. The gas storage tank provides a stable gas source for backflushing dust removal. The gas distribution box evenly distributes the compressed gas from the gas storage tank to each backflushing pipe. Designed as a pressure vessel, the gas distribution box is equipped with a pressure gauge, an inlet valve, and a drain valve. The pressure gauge displays the compressed gas pressure in the gas distribution box in real time. The inlet valve controls the supply of compressed gas from the gas storage tank to the gas distribution box. The drain valve, installed at the bottom of the gas distribution box, periodically discharges condensate, oil, or other impurities from the box. The two ends of the backflush pipe are connected to the channels of the gas distribution box and the high-temperature resistant metal filter bag 6, respectively. The backflush pipe delivers the gas distributed and output by the gas distribution box to the corresponding high-temperature resistant metal filter bag 6. A pulse valve is installed on the connecting pipe between the gas distribution box and the backflush pipe. The size of the pulse valve is selected according to the number of high-temperature resistant metal filter bags 6 in each row. When dust removal is required, the pulse valve opens instantly, so that the compressed gas in the gas distribution box is quickly sprayed into the high-temperature resistant metal filter bag 6 through the backflush pipe to achieve pulse-type dust removal.

[0024] In this embodiment, the pressure difference between the inside and outside of the high-temperature resistant metal filter bag 6 is monitored in real time. When the pressure difference reaches the set value, the gas storage tank of the back-blowing dust removal device 5 blows compressed gas of 0.3MPa to 0.6MPa into the high-temperature resistant metal filter bag 6 at its lower end through the gas distribution box and back-blowing pipe. At the same time, a certain amount of clean air chamber gas and dust intercepted on the outer surface of the filter bag are blown into the high-temperature resistant metal filter bag 6.

[0025] The high-temperature resistant metal filter bags 6 have a longitudinal spacing of 200mm to 250mm and a transverse spacing of 200mm to 250mm. They are fixed to each perforated plate hole on the inner wall of the device body 2 using special sealing flanges. When the length of the high-temperature resistant metal filter bags 6 exceeds 6m, their bottoms need to be fixed to prevent the high-temperature resistant metal filter bags 6 from shaking and causing wear between the filter bags. Since the high-temperature resistant metal filter bags 6 are rigid filter materials, to avoid the mounting holes scratching the surface of the filter bags, the diameter of the perforated plate holes is 10mm larger than the outer diameter of the filter bags. The high-temperature resistant metal filter bags 6 are made of 310S or 316 stainless steel, and can withstand temperatures up to 450℃ to 600℃ for extended periods, which is sufficient to meet the operating temperature of high-temperature denitrification catalysts. The stainless steel high-temperature resistant metal filter bags 6 have strong corrosion resistance and can resist corrosion from dry alkaline desulfurizing agents. The desulfurizing agent and dust combine and adhere to the surface of the high-temperature resistant metal filter bags 6, which can further react with sulfur dioxide to improve desulfurization efficiency.

[0026] In this embodiment, the number of integrated flue gas purification devices used for high-temperature flue gas desulfurization, dust removal, and denitrification, as well as the diameter of the internal device body, can be varied according to the amount of flue gas to be processed. The upper end of the device body 2 is connected to a fixed conical hopper with a tubular end cap, which can be disassembled to replace the catalyst and metal filter bag. To ensure that the dust collector hopper at the lower end of the device body 2 does not become clogged, the conical angle of the dust collector hopper is between 60° and 70°.

[0027] As a further preferred embodiment, heat-insulating and anti-scalding materials are installed along the outer wall of the device body 2 to ensure stable operating temperature and prevent personnel from being scalded during operation and maintenance. If necessary, steam tracing can also be installed on the outside of the device body 2 to regulate the internal temperature of the flue gas purification device.

[0028] Furthermore, on the main body 2 of the device, sliding supports are made at the locations where the high-temperature resistant metal filter bag 6 and the high-temperature denitrification catalyst 3 are installed, respectively, to fix the main body 2 of the device to the steel structure frame.

[0029] Based on the above-mentioned integrated flue gas purification device that can be used for high-temperature flue gas desulfurization, dust removal, and denitrification, the specific implementation method is as follows: After being cooled and pre-dust-removed, the flue gas at 300-400°C is mixed with denitrified ammonia gas in a dry desulfurization reactor before entering an integrated flue gas purification device for high-temperature flue gas desulfurization, dust removal, and denitrification.

[0030] Flue gas enters the device body 2 through the inlet pipe and valve assembly 1. The flue gas is filtered by the high-temperature resistant metal filter bag 6 installed on the tube sheet in the device body 2. Dust particles, desulfurization products, and unreacted active calcium-based desulfurizing agent are all intercepted on the surface of the high-temperature resistant metal filter bag 6. Since the filtration velocity on the surface of the metal filter bag is only 0.6~0.8m / min, the unreacted desulfurizing agent and a small amount of residual SO2 continue to react, ultimately ensuring that SO2 and particulate matter meet emission standards.

[0031] Ammonia gas passes smoothly through the high-temperature resistant metal filter bag 6, continues to rise, passes through the high-temperature metal compensator 4, and reaches the high-temperature denitrification catalyst 3 installed at the upper end of the device body 2. Under the action of the catalyst, NOx reacts with ammonia gas to produce nitrogen gas and water, achieving the purpose of removing nitrogen oxides. Finally, the qualified gas after desulfurization, dust removal, and denitrification is discharged from the entire device through the exhaust pipe and valve assembly 7. Under the action of the induced draft fan, it enters the subsequent medium and low temperature waste heat recovery device to recover waste heat before being discharged into the atmosphere through the chimney.

[0032] Dust, desulfurization products, and a small amount of unreacted desulfurizing agent remaining on the surface of the high-temperature resistant metal filter bag 6 are blown off by the back-flushing cleaning device 5 into the conical ash hopper of the device body 2. When the ash reaches the level gauge height, it is discharged through the ash discharge device and then sent to the ash silo for storage via the ash conveying device. The back-flushing cleaning device 5 uses compressed air or compressed nitrogen as the back-flushing air source, and the back-flushing cleaning program can adopt timed cleaning or constant pressure differential cleaning.

[0033] The inlet pipe and valve assembly 1 and the outlet pipe and valve assembly 7 consist of flue gas ducts and manual or automatic flue gas valves. Depending on the flue gas volume, multiple purification devices can be connected in parallel to meet the flue gas treatment capacity. Each purification device can operate independently and can be disconnected or connected to the entire system through the inlet pipe and valve assembly 1 and the outlet pipe and valve assembly 7.

[0034] The above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although the utility model has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of this utility model. Any modifications or equivalent substitutions that do not depart from the spirit and scope of this utility model should be covered within the protection scope of the claims of this utility model.

Claims

1. An integrated flue gas purification device for high-temperature flue gas desulfurization, dust removal, and denitrification, characterized in that, It includes an air inlet pipe and valve assembly (1) and an air outlet pipe and valve assembly (7). The air inlet pipe and valve assembly (1) and the air outlet pipe and valve assembly (7) are fixed to the upper and lower ends of the device body (2), respectively. The inside of the device body (2) is provided with a high temperature denitrification catalyst (3), a high temperature metal compensator (4), a backflushing cleaning device (5), and a high temperature resistant metal filter bag (6) from top to bottom.

2. The integrated flue gas purification device according to claim 1, wherein, The device body (2) is a cylindrical shell with an inverted cone at the top. The large diameter end of the cone is connected and fixed to the upper end of the device body (2). The small diameter end of the cone is connected to a tubular end cap through a flange. The outer end of the end cap is connected to an air duct valve assembly (7). The air duct valve assembly (7) is responsible for discharging the purified gas from the device. The valves are pneumatic.

3. The integrated flue gas purification device according to claim 1, wherein, The lower part of the device body (2) is a dust collector hopper with a conical tube body. One side of the dust collector hopper is connected to an air inlet pipe and valve assembly (1). The air inlet pipe and valve assembly (1) is responsible for introducing dust-laden flue gas into the device. The valves are manual or pneumatic.

4. The integrated flue gas purification device according to claim 1, wherein, The upper part of the device body (2) is a catalytic section, which is equipped with a high-temperature denitrification catalyst (3). The device body (2) is equipped with a support grid, and the high-temperature denitrification catalyst (3) is placed on the support grid.

5. The integrated flue gas purification device according to claim 4, wherein, The high-temperature denitrification catalyst (3) is made of vanadium-titanium and tungsten-titanium materials, and its applicable temperature is 300℃~400℃.

6. The integrated flue gas purification device according to claim 4, wherein, The high-temperature denitrification catalyst (3) is equipped with a purification device at the lower end, and a high-temperature resistant metal compensator (4) is provided in the upper middle part of the purification device. The high-temperature resistant metal compensator (4) is made of stainless steel and has a temperature resistance of up to 450℃. The diameter of the high-temperature resistant metal compensator (4) is 2~5m and its pressure resistance meets 0.1MPa.

7. The integrated flue gas purification device according to claim 1, wherein, The lower part of the high-temperature resistant metal compensator (4) is the desulfurization and dust removal section. The lower end of the desulfurization and dust removal section is equipped with a back-blowing cleaning device (5). The back-blowing cleaning device (5) adopts a row-jet blowing arrangement.

8. The integrated flue gas purification device according to claim 1, wherein, The lower end of the back-flushing cleaning device (5) is provided with a high-temperature resistant metal filter bag (6), and the inside of the device body (2) is provided with a perforated plate. The high-temperature resistant metal filter bag (6) is fixed to each perforated plate hole on the inner wall of the device body (2) by a sealing flange.

9. The integrated flue gas purification device according to claim 8, wherein, The high-temperature resistant metal filter bag (6) is made by pressing stainless steel metal powder and then sintering it. The longitudinal spacing of the high-temperature resistant metal filter bag (6) is 200mm~250mm, the transverse spacing is 200mm~250mm, and the temperature range of the high-temperature resistant metal filter bag (6) is 450℃~600℃.

10. The integrated flue gas purification device according to claim 1, wherein, The lower end of the device body (2) is a dust collector hopper with a conical tube body, and the angle of the dust collector hopper is between 60° and 70°.

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