Combined flue gas cleaning device and method

Abstract

The application provides a combined flue gas purification device and method, and belongs to the technical field of flue gas purification. The device comprises a booster fan a, which is connected with flue gas containing pollutants on the upstream side and connected with a flue gas heat exchanger on the downstream side. The rear end of the flue gas heat exchanger is connected with an adsorption tower module, which comprises an active coke desulfurization tower and an active coke dust removal tower connected in communication. The rear end of the adsorption tower module is connected with the inlet of a GGH flue gas heat exchanger, the outlet of the GGH flue gas heat exchanger is connected to a heat supplement device, the downstream side of the heat supplement device is connected with an ammonia injection module, the downstream side of the ammonia injection module is connected with a denitration reactor, and the outlet of the denitration reactor is connected to a chimney through a denitration induced draft fan. The application adopts the active coke flue gas purification technology for desulfurization, adopts the active coke flue gas purification technology for dust removal, and adopts the SCR process for denitration. In full consideration of the influence of dust on the SCR process, the flue gas desulfurization, denitration and dust removal can be realized without increasing the bag dust removal.

Description

Technical Field

[0001] This invention belongs to the field of flue gas purification technology, specifically relating to a combined flue gas purification device and method for activated coke desulfurization, activated coke dust removal, and SCR denitrification. Background Technology

[0002] Activated coke flue gas purification technology can remove sulfides, nitrogen oxides, particulate matter, dioxins and heavy metals from flue gas. It is an integrated process technology for removing multiple pollutants. SCR flue gas denitrification technology is a process technology in which nitrogen oxides in flue gas react with reducing agent NH3 to generate N2 under the conditions of catalyst and certain temperature.

[0003] In existing technologies, the use of integrated activated coke technology for ultra-low emission treatment of flue gas, while ensuring that nitrogen oxides meet the standards, poses a risk of ammonia escape, and the integrated activated coke technology also poses a risk of dust not meeting the standards.

[0004] In the existing technology, the coupled treatment technology of activated coke and SCR does not take into account the impact of substandard activated coke dust on the SCR device, and the SCR does not have the function of dust removal, resulting in the system dust concentration not meeting the standard.

[0005] In existing technologies, the coupling of activated coke desulfurization bag filter dust removal and SCR denitrification technology has the disadvantages of large footprint, high initial investment and operating costs.

[0006] Therefore, in activated coke systems, how to ensure that the outlet dust concentration and ammonia escape meet the standards without installing expensive and large-footprint baghouse dust collectors is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] To overcome the shortcomings of existing technologies, this invention provides a combined flue gas purification device and method for activated coke desulfurization, activated coke dust removal, and SCR denitrification. It uses activated coke flue gas purification technology for desulfurization and dust removal, and SCR process for denitrification. By fully considering the impact of dust on the SCR process, flue gas desulfurization, denitrification, and dust removal can be achieved without adding bag filters.

[0008] The technical solution adopted by the present invention to solve its technical problem is: a combined flue gas purification device, including a booster fan a, the upstream of which is connected to flue gas containing pollutants, and the downstream of which is connected to a flue gas heat exchanger. The downstream of the flue gas heat exchanger is connected to an adsorption tower module, which includes an activated coke desulfurization tower and an activated coke dust removal tower connected in series. The downstream of the adsorption tower module is connected to the inlet of a GGH flue gas heat exchanger, and the outlet of the GGH flue gas heat exchanger is connected to a supplementary heating device. The downstream of the supplementary heating device is connected to an ammonia injection module, and the downstream of the ammonia injection module is connected to a denitrification reactor. The outlet of the denitrification reactor is connected to a chimney through a denitrification induced draft fan.

[0009] Furthermore, the bottom outlet of the activated coke desulfurization tower is connected to the regeneration tower conveying equipment, the regeneration tower conveying equipment is connected to the regeneration tower inlet, the regeneration tower outlet is connected to the vibrating screen, the downstream of the vibrating screen is connected to the air screen, the downstream of the air screen is connected to the adsorption tower conveying equipment, and the adsorption tower conveying equipment is connected to the top inlet of the activated coke desulfurization tower and the activated coke dust removal tower.

[0010] In one embodiment, the bottom outlet of the activated coke dust collector is connected to the inlet of the regeneration tower via a regeneration tower conveying device.

[0011] In another implementation, the bottom outlet of the activated coke dust removal tower is connected to the front end pipe of the vibrating screen.

[0012] In one embodiment, the activated coke desulfurization tower and the activated coke dust removal tower are connected by a cavity.

[0013] In another implementation, there is no cavity between the activated coke desulfurization tower and the activated coke dust removal tower; they are separated by a perforated plate, a fish-scale plate, or a grid plate.

[0014] A combined flue gas purification method using the aforementioned apparatus involves the following steps: Flue gas containing pollutants from upstream is pressurized by a booster fan (a), then heats up through a flue gas heat exchanger before entering an activated coke desulfurization tower. After desulfurization in the activated coke desulfurization tower, the flue gas enters an activated coke dust removal tower. After dust removal, the flue gas enters a GGH flue gas heat exchanger. After heat exchange in the GGH flue gas heat exchanger, the flue gas is further heated by a supplementary heating device before entering an ammonia injection module. In the ammonia injection module, the flue gas and ammonia are thoroughly mixed. The flue gas then enters a denitrification reactor to complete denitrification. Finally, after being pressurized by a denitrification induced draft fan, the clean flue gas is discharged into the atmosphere through a chimney.

[0015] Furthermore, the activated coke that is saturated with adsorption in the activated coke desulfurization tower is transported to the regeneration tower through the regeneration tower conveying equipment. The regenerated activated coke is discharged from the bottom outlet of the regeneration tower and is then screened by a vibrating screen and an air screen in sequence. Finally, the activated coke is transported by the adsorption tower conveying equipment to the activated coke desulfurization tower and the activated coke dust removal tower for recycling.

[0016] In one implementation, activated coke that has trapped dust in the activated coke dust removal tower is transported to the regeneration tower via a regeneration tower conveying device. After being regenerated together with the activated coke that has been saturated with adsorption in the activated coke desulfurization tower, the activated coke is then screened by a vibrating screen and an air screen in sequence. The activated coke is then transported to the activated coke desulfurization tower and the activated coke dust removal tower by the adsorption tower conveying device for recycling.

[0017] In another implementation, the activated coke that has intercepted dust in the activated coke dust removal tower is transported to the front pipeline of the vibrating screen via a special conveying device. After being screened by the vibrating screen and the air screen in sequence, the activated coke is transported by the adsorption tower conveying device to the activated coke desulfurization tower and the activated coke dust removal tower for recycling.

[0018] The beneficial effects of this invention include: 1. The device does not generate solid waste or secondary pollutants; 2. The dust removal process does not use traditional bag filters, so it occupies a small area and requires less investment; 3. The SCR denitrification process can effectively guarantee denitrification efficiency; 4. It avoids the risk of ammonia escape from the system. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the device of the present invention.

[0020] In the diagram: 1-Booster fan a; 2-Flue gas heat exchanger; 3-Activated coke desulfurization tower; 4-Activated coke dust removal tower; 5-GGH flue gas heat exchanger; 6-Reheating device; 7-Ammonia injection module; 8-Denitrification reactor; 9-Denitrification induced draft fan; 10-Chimney; 11-Regeneration tower conveying equipment; 12-Regeneration tower; 13-Vibrating screen; 14-Air screen; 15-Adsorption tower conveying equipment; 16-Booster fan b;

[0021] 31-Inlet chamber of activated coke desulfurization tower; 32-Bed a of activated coke desulfurization tower; 33-Bed b of activated coke desulfurization tower; 34-Baffle plate of activated coke desulfurization tower; 41-Inlet chamber of activated coke dust removal tower; 42-Bed a of activated coke dust removal tower; 43-Bed b of activated coke dust removal tower; 44-Outlet chamber of activated coke dust removal tower; 45-Baffle plate of activated coke dust removal tower. Detailed Implementation

[0022] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] In the description of this invention, it should be noted that the terms "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0024] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0025] A combined flue gas purification device and method for activated coke desulfurization, activated coke dust removal, and SCR denitrification is disclosed. Flue gas containing pollutants from upstream is pressurized by a booster fan a1, then heats up to a suitable temperature in a flue gas heat exchanger 2 before entering an activated coke desulfurization tower 3. After desulfurization in the activated coke desulfurization tower 3, the flue gas enters an activated coke dust removal tower 4. After dust removal, the flue gas enters a GGH flue gas heat exchanger 5. After heat exchange in the GGH flue gas heat exchanger 5, the flue gas is further heated by a supplementary heating device 6 to the optimal temperature for the denitrification catalyst before entering an ammonia injection module 7. In the ammonia injection module 7, the flue gas and ammonia are fully mixed before entering a denitrification reactor 8 to complete the denitrification process. Finally, after being pressurized by a denitrification induced draft fan 9, the clean flue gas is discharged into the atmosphere through a chimney 10.

[0026] The activated coke desulfurization tower 3 and the activated coke dust removal tower 4 can be connected by a cavity, or they can be separated by a perforated plate, a "fish scale plate" or a grid plate without leaving a cavity.

[0027] The activated coke desulfurization tower 3 is divided into different activated coke desulfurization tower beds by an activated coke desulfurization tower partition plate 34. The moving speed of the activated coke in each bed is controlled by the corresponding unloader at the bottom. The activated coke desulfurization tower partition plate 34 is in the form of a perforated plate, a "fish scale plate", or a grid plate. The number of fast and slow beds in the activated coke desulfurization tower 3 is 2 to 4, preferably 3.

[0028] The activated coke dust collector 4 is divided into different activated coke dust collector beds by an activated coke dust collector partition plate 45. The moving speed of the activated coke in each bed is controlled by the corresponding unloader at the bottom. The activated coke dust collector partition plate 45 is in the form of a perforated plate, a "fish scale plate", or a grid plate. The number of fast and slow beds in the activated coke dust collector 4 is 1 to 4, preferably 2.

[0029] At the bottom outlet of activated coke desulfurization tower 3, the saturated activated coke is transported to regeneration tower 12 through regeneration tower conveying equipment 11. The regenerated activated coke is discharged from the bottom of regeneration tower 12, and after being screened by vibrating screen 13 and air screen 14, it is transported to activated coke desulfurization tower 3 and activated coke dust removal tower 4 by adsorption tower conveying equipment 15 for recycling.

[0030] In one embodiment, at the bottom outlet of the activated coke dust removal tower 4, the activated coke that has intercepted dust is conveyed to the regeneration tower 12 via the conveying device 11. After being regenerated together with the activated coke that has been saturated with adsorption in the activated coke desulfurization tower 3, the activated coke is screened by the vibrating screen 13 and the air screen 14, and then conveyed by the adsorption tower conveying device 15 to the activated coke desulfurization tower 3 and the activated coke dust removal tower 4 for recycling.

[0031] In another implementation, at the bottom outlet of the activated coke dust removal tower 4, the activated coke that has intercepted dust can be transported to the front pipe of the vibrating screen 13 via a special conveying device. After being screened by the vibrating screen 13 and the air screen 14, the activated coke is transported by the adsorption tower conveying device 15 to the activated coke desulfurization tower 3 and the activated coke dust removal tower 4 for recycling.

[0032] The activated coke desulfurization tower 3 and the activated coke dust removal tower 4 adopt a modular design and are integrated into an adsorption tower module. In a system device, the number of adsorption tower modules is 1 to 10, preferably 1 to 8.

[0033] The desulfurization mechanism of activated coke relies on the adsorption effect of micropores, which adsorb sulfides in flue gas into its micropores, and then discharge the sulfides from the micropores through the activated coke desorption process. The dust removal mechanism of activated coke utilizes the filtration effect of activated coke particles, making the adsorption layer equivalent to a high-efficiency particulate filter. Under the action of inertial collision and interception effect, most of the dust particles in the flue gas are removed. The denitrification mechanism of activated coke involves injecting NH3 into the flue gas, where nitrogen oxides and ammonia in the flue gas undergo a catalytic reduction reaction on the surface of activated coke to generate nitrogen.

[0034] Example 1

[0035] like Figure 1 As shown in this embodiment, a combined flue gas purification device and process for activated coke desulfurization, activated coke dust removal, and SCR denitrification is provided. The flue gas containing pollutants comes from the sintering main exhaust fan. The flue gas parameters are: the flue gas flow rate at the main exhaust fan outlet is 1,018,000 Nm³. 3 / h, inlet SO2 concentration 1500 mg / Nm 3 Inlet NOx concentration 400 mg / Nm 3 Ingested particulate matter 100 mg / Nm 3 The flue gas emission standard requires an outlet SO2 concentration of 35 mg / Nm³. 3 Inlet NOx concentration 50 mg / Nm 3 Ingested particulate matter 10 mg / Nm 3 .

[0036] The process flow of Example 1 is as follows: After the flue gas is pressurized by the booster fan 1, it is heated to a suitable temperature by the flue gas heat exchanger 2 and then enters the activated coke desulfurization tower 3. After desulfurization in the activated coke desulfurization tower 3, the flue gas enters the activated coke dust removal tower 4. After dust removal, the flue gas enters the GGH flue gas heat exchanger 5. After heat exchange, the flue gas is heated to the most suitable temperature for the denitrification catalyst by the supplementary heating device 6 and then enters the ammonia injection module 7. In the ammonia injection module 7, the flue gas and ammonia are fully mixed and then enter the denitrification reactor 8 to complete the denitrification of the flue gas. After being pressurized by the denitrification induced draft fan 9, the clean flue gas is discharged into the atmosphere through the chimney 10.

[0037] In the above implementation scheme, there is no cavity between the activated coke desulfurization tower 3 and the activated coke dust removal tower 4, and the activated coke desulfurization tower 3 and the activated coke dust removal tower 4 are separated by a perforated plate.

[0038] The activated coke desulfurization tower 3 is divided into two beds, a fast bed and a slow bed, by a perforated plate. The moving speed of the activated coke in the fast bed and the slow bed is controlled by the corresponding unloaders at the bottom. Specifically, the activated coke desulfurization tower 3 includes an inlet chamber 31, bed a32, and bed b33 connected in sequence. Bed a32 and bed b33 are separated by a partition plate 34.

[0039] The activated coke dust removal tower 4 is divided into two beds by a perforated plate. The moving speed of the activated coke in the fast and slow beds is controlled by the corresponding unloaders at the bottom. Specifically, the activated coke dust removal tower 4 includes an inlet chamber 41, bed a42, bed b43, and outlet chamber 44 connected in sequence. The inlet chamber 41 is connected to bed b33, and bed a42 and bed b43 are separated by a partition plate 45.

[0040] The activated coke saturated at the bottom of the activated coke desulfurization tower 3 is transported to the regeneration tower 12 through the regeneration tower conveying device 11. The activated coke regenerated at the bottom of the regeneration tower 12 is screened by the vibrating screen 13 and the air screen 14, and then transported by the adsorption tower conveying device 15 to the activated coke desulfurization tower 3 and the activated coke dust removal tower 4 for recycling.

[0041] The activated coke that has trapped dust at the bottom of the activated coke dust removal tower 4 is conveyed to the regeneration tower 12 by the conveying device 11. After being regenerated together with the activated coke that has been saturated by adsorption in the activated coke desulfurization tower 3, it is screened by the vibrating screen 13 and the air screen 14. Then, the activated coke is conveyed by the adsorption tower conveying device 15 to the activated coke desulfurization tower 3 and the activated coke dust removal tower 4 for recycling.

[0042] In the above implementation scheme, the activated coke desulfurization tower 3 and the activated coke dust removal tower 4 adopt a modular design, with a total of 7 modules for the activated coke desulfurization tower 3 and the activated coke dust removal tower 4. The heat exchange medium of the flue gas heat exchanger 2 is air, which exchanges heat with the sintering flue gas. Preferably, the air after heat exchange can be transported to the supplementary heating device 6 by the booster fan b16. The supplementary heating device 6 can be a hot air furnace or a built-in burner, etc.

[0043] The temperature of the flue gas after heat exchange in flue gas heat exchanger 2 is 135-140℃. The flue gas temperature when entering GGH flue gas heat exchanger 5 is controlled within the range of 125-130℃. The flue gas temperature after heat exchange in GGH flue gas heat exchanger 5 is controlled within the range of 280-285℃. The flue gas temperature after heat supplementation by heat supplementation device 6 is controlled within the range of 310-320℃.

[0044] Example 2

[0045] This embodiment provides a combined flue gas purification device and process for activated coke desulfurization, activated coke dust removal, and SCR denitrification. The flue gas containing pollutants comes from the main exhaust fan of the pellet plant. The flue gas parameters are: the flue gas flow rate at the main exhaust fan outlet is 626,000 m³ / h. 3 / h, inlet SO2 concentration 1300 mg / Nm 3 Inlet NOx concentration 300 mg / Nm 3 Ingested particulate matter 100 mg / Nm 3 The flue gas emission standard requires an SO2 concentration of 30 mg / Nm³ at the outlet. 3 Inlet NOx concentration 30 mg / Nm 3 Ingested particulate matter 10 mg / Nm 3 .

[0046] The process flow of Example 2 is as follows: After the flue gas is pressurized by the booster fan 1, it is heated to a suitable temperature by the flue gas heat exchanger 2 and enters the activated coke desulfurization tower 3. After desulfurization in the activated coke desulfurization tower 3, the flue gas enters the activated coke dust removal tower 4. After dust removal, the flue gas enters the GGH flue gas heat exchanger 5. After heat exchange, the flue gas is heated to the most suitable temperature for the denitrification catalyst by the supplementary heating device 6 and then enters the ammonia injection module 7. In the ammonia injection module 7, the flue gas and ammonia are fully mixed and then enter the denitrification reactor 8 to complete the denitrification of the flue gas. After being pressurized by the denitrification induced draft fan 9, the clean flue gas is discharged into the atmosphere through the chimney 10.

[0047] In the above implementation scheme, there is a 1000mm cavity between the activated coke desulfurization tower 3 and the activated coke dust removal tower 4, which serves as a maintenance passage between the activated coke desulfurization tower 3 and the activated coke dust removal tower 4.

[0048] The activated coke desulfurization tower 3 is divided into three beds (fast bed and slow bed) by a perforated plate. The movement speed of the activated coke in each of the three beds is controlled by the corresponding unloader at the bottom. The activated coke dust removal tower 4 is a single, integrated bed, and the movement speed of the activated coke is controlled by the unloader at the bottom.

[0049] At the bottom of the activated coke dust removal tower 4, the activated coke that has intercepted dust is transported to the front pipe of the vibrating screen 13 through a special conveying device. After being screened by the vibrating screen 13 and the air screen 14, the activated coke is transported by the adsorption tower conveying device 15 to the activated coke desulfurization tower 3 and the activated coke dust removal tower 4 for recycling.

[0050] The activated coke desulfurization tower 3 and the activated coke dust removal tower 4 adopt a modular design, with a total of 4 modules for the activated coke desulfurization tower 3 and the activated coke dust removal tower 4.

[0051] The heat exchange medium in flue gas heat exchanger 2 is circulating cooling water, which exchanges heat with the sintering flue gas. The temperature after heat exchange in flue gas heat exchanger 2 is 130–135℃. The flue gas temperature entering GGH flue gas heat exchanger 5 is controlled within the range of 130–135℃. The flue gas temperature after heat exchange in GGH flue gas heat exchanger 5 is controlled within the range of 250–255℃. The flue gas temperature after supplementary heating by supplementary heating device 6 is controlled within the range of 280–290℃.

[0052] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A combined flue gas purification method, wherein the method uses a combined flue gas purification device, characterized in that, The combined flue gas purification device includes a booster fan a (1), which is connected upstream to flue gas containing pollutants and downstream to a flue gas heat exchanger (2). The flue gas heat exchanger (2) is connected downstream to an adsorption tower module. The adsorption tower module includes an activated coke desulfurization tower (3) and an activated coke dust removal tower (4) connected in series. The adsorption tower module is connected downstream to the inlet of a GGH flue gas heat exchanger (5). The outlet of the GGH flue gas heat exchanger (5) is connected to a supplementary heating device (6). The supplementary heating device (6) is connected downstream to an ammonia injection module (7). The ammonia injection module (7) is connected downstream to a denitrification reactor (8). The outlet of the denitrification reactor (8) is connected to a chimney (10) via a denitrification induced draft fan (9). The bottom outlet of the activated coke desulfurization tower (3) is connected to the regeneration tower conveying equipment (11), the regeneration tower conveying equipment (11) is connected to the inlet of the regeneration tower (12), the outlet of the regeneration tower (12) is connected to the vibrating screen (13), the downstream of the vibrating screen (13) is connected to the air screen (14), the downstream of the air screen (14) is connected to the adsorption tower conveying equipment (15), and the adsorption tower conveying equipment (15) is connected to the top inlet of the activated coke desulfurization tower (3) and the activated coke dust removal tower (4); The combined flue gas purification method is as follows: the flue gas containing pollutants from upstream is pressurized by the booster fan a (1), and after heat exchange by the flue gas heat exchanger (2), it enters the activated coke desulfurization tower (3). After desulfurization in the activated coke desulfurization tower (3), the flue gas enters the activated coke dust removal tower (4). After dust removal, the flue gas enters the GGH flue gas heat exchanger (5). After heat exchange in the GGH flue gas heat exchanger (5), the flue gas is heated by the heat replenishment device (6) and then enters the ammonia injection module (7). In the ammonia injection module (7), the flue gas and ammonia are fully mixed, and then enter the denitrification reactor (8) to complete the denitrification of the flue gas. After being pressurized by the denitrification induced draft fan (9), the clean flue gas is discharged into the atmosphere through the chimney (10).

2. The combined flue gas purification method according to claim 1, characterized in that, The bottom outlet of the activated coke dust removal tower (4) is connected to the inlet of the regeneration tower (12) via the regeneration tower conveying equipment (11).

3. The combined flue gas purification method according to claim 1, characterized in that, The bottom outlet of the activated coke dust removal tower (4) is connected to the front end pipe of the vibrating screen (13).

4. The combined flue gas purification method according to claim 1, characterized in that, The activated coke desulfurization tower (3) and the activated coke dust removal tower (4) are connected by a cavity.

5. The combined flue gas purification method according to claim 1, characterized in that, There is no cavity between the activated coke desulfurization tower (3) and the activated coke dust removal tower (4), and they are separated by a perforated plate, fish scale plate or grid plate.

6. The combined flue gas purification method according to claim 1, characterized in that, The activated coke saturated in the activated coke desulfurization tower (3) is transported to the regeneration tower (12) through the regeneration tower conveying equipment (11). The regenerated activated coke is discharged from the bottom outlet of the regeneration tower (12), and after being screened by the vibrating screen (13) and the air screen (14) in sequence, the activated coke is transported to the activated coke desulfurization tower (3) and the activated coke dust removal tower (4) by the adsorption tower conveying equipment (15) for recycling.

7. The combined flue gas purification method according to claim 6, characterized in that, The activated coke that has trapped dust in the activated coke dust removal tower (4) is transported to the regeneration tower (12) via the regeneration tower conveying equipment (11). After being regenerated together with the activated coke that has been saturated with adsorption in the activated coke desulfurization tower (3), the activated coke is then screened by the vibrating screen (13) and the air screen (14) in sequence. The activated coke is then transported to the activated coke desulfurization tower (3) and the activated coke dust removal tower (4) by the adsorption tower conveying equipment (15) for recycling.

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