A multi-pollutant co-treatment device for flue gas

Abstract

This utility model discloses a multi-pollutant co-treatment device for flue gas, belonging to the field of environmental engineering technology. The co-treatment device consists of a flue gas inlet pipe, a grinding and feeding assembly, a Venturi reactor, a primary reactor, a throat, a secondary reactor, a gas guide pipe, a bag filter, an ash hopper, a screw conveyor, and a recycled ash grinding and feeding machine. The recycled ash grinding and feeding machine is installed on the screw conveyor and connected to the primary reactor. The bag filter, ash hopper, screw conveyor, and recycled ash grinding and feeding machine are cyclically connected to the Venturi reactor, allowing for secondary reuse of the dust. This significantly reduces operating costs while improving pollutant removal efficiency. The unique reactor design achieves thorough and uniform gas-solid mixing and reaction. The reactor setup is flexible, with a gradually decreasing cross-sectional area in the contraction section to increase gas velocity. The throat maintains a constant cross-sectional area to sustain high-speed flow. The reaction reagents are readily available and inexpensive, resulting in low overall operating costs.

Description

Technical Field

[0001] This utility model relates to a multi-pollutant synergistic treatment device for flue gas, belonging to the field of environmental engineering technology. Background Technology

[0002] With the popularization and use of clean production technologies and clean energy in various industries across China, the initial pollutant emission concentrations of flue gas from existing industrial boilers and kilns have significantly decreased (generally below 1000 mg / m³). 3 Compared with wet desulfurization technology, dry desulfurization technology has advantages such as simple process, no wastewater and waste acid discharge, no corrosion, low investment cost, no "white smoke", and good public perception, which are very much in line with my country's national conditions and the technological development trend in the field of flue gas treatment. However, existing dry desulfurization technologies still have technical bottlenecks such as slow reaction speed, uneven gas-solid mixing, large reagent consumption, and high operating costs, making it difficult to fully meet the stringent requirements of modern environmental protection. Therefore, it is urgent to break through the bottlenecks of equipment such as high-efficiency gas-solid mixing reactors. CN202411832982.0 discloses a high-efficiency and energy-saving dry desulfurization device for coal-fired boilers, including a desulfurizing agent spraying device and a water mist spraying device. This invention improves the desulfurization reaction effect of the dry desulfurization device for coal-fired boilers and reduces the waste of desulfurization resources by setting up the water mist spraying device and controlling the water mist spraying volume of the water mist spraying device. CN202411042310.X provides a double-cone reactor fixed-bed dry desulfurization device, including a reactor, a fixed bed, a feeding device, and a discharging device. The flue gas is purified through multi-stage bed laminar flow purification, with good desulfurization effect, fast and uniform unloading, and online unloading and loading.

[0003] The above-mentioned equipment can achieve efficient desulfurization, but it also has disadvantages such as high gas resistance, relatively complex structure, and high consumption of reagents.

[0004] Therefore, it is necessary to develop a dry flue gas multi-pollutant co-treatment device with low gas resistance, uniform gas-solid mixing, and low reagent consumption to improve the above-mentioned shortcomings. Utility Model Content

[0005] The main purpose of this invention is to provide a device for the synergistic treatment of multiple pollutants in flue gas.

[0006] The objective of this utility model can be achieved by adopting the following technical solution: A multi-pollutant co-treatment device for flue gas includes a flue gas inlet pipe for guiding gas, a Venturi reactor is installed at one end of the flue gas inlet pipe, a primary reactor is installed at the outer end of the Venturi reactor, a throat and a secondary reactor are installed at the outer end of the primary reactor, and a gas guide pipe is installed at the outer end of the secondary reactor. The outer end of the air duct is connected to a bag filter, the bottom of the bag filter is connected to a dust hopper, and the bottom of the dust hopper is connected to a dust bin. The ash hopper is connected to a screw conveyor on one side, and a recycled ash grinding and feeding machine is installed on the screw conveyor. The recycled ash grinding and feeding machine is connected to the diffusion section of the Venturi reactor. The bag filter, ash hopper, screw conveyor and recycled ash grinding and feeding machine are cyclically connected to the Venturi reactor. The outer side of the bag filter is connected to a purified flue gas outlet pipe. A grinding and feeding assembly is installed at the upper end of the flue gas inlet pipe.

[0007] Preferably, the primary reactor and the secondary reactor are respectively composed of a bottom diffuser section cone bottom, a middle cylindrical body, and an upper contraction section cone top, and are equipped with flue gas distribution plates inside; The primary reactor and the secondary reactor are connected by a throat pipe, and the residence time of the flue gas in the primary reactor is 3-10 seconds. The residence time of the flue gas in the secondary reactor is 2-5 seconds.

[0008] Preferably, the grinding and feeding assembly consists of a grinding and feeding machine and a reagent storage silo; A grinding feeder is installed at the upper end of the flue gas inlet pipe at the bottom of the Venturi reactor, and a reagent storage bin is connected to the grinding feeder.

[0009] Preferably, the conical contraction section of the Venturi reactor has an angle of 20-25°, the ratio of the throat diameter to the flue gas inlet diameter is 0.3-0.5:1, and the diffusion section angle is 10-15°.

[0010] Preferably, the ratio of the diameter of the cylindrical throat between the primary reactor and the secondary reactor to the diameter of the flue gas inlet pipe is 0.5-2:1, and the ratio of the length of the cylindrical throat between the primary reactor and the secondary reactor to the diameter of the flue gas inlet pipe is 0.5-2:1. The diameter of the cylindrical body of the primary reactor and the secondary reactor is 3-8 times the diameter of the flue gas inlet pipe.

[0011] The beneficial technical effects of this utility model are as follows: This utility model provides a multi-pollutant synergistic treatment device for flue gas. 1) Flue gas flows into the Venturi reactor through the flue gas inlet pipe. The reagents from the reagent storage silo are: calcium hydroxide, sodium bicarbonate, and high specific surface area porous reactive material. They are quantitatively added to the grinding feeder and ground to a certain particle size of 200-1000 mesh. They are then added into the flue gas inlet pipe and vigorously mixed with the flue gas at a certain temperature (120-300℃) in the Venturi reactor. The Venturi reactor consists of four parts: an inlet cylindrical section, a conical contraction section, a cylindrical throat, and a diffusion section. The length of the inlet section is equal to the pipe diameter. The angle of the conical contraction section is 20-25°. The ratio of the throat diameter to the pipe diameter is 0.3-0.5:1. The angle of the diffusion section is controlled at 6-16°. The cross-sectional area of ​​the contraction section gradually decreases, which increases the gas flow rate. The throat maintains a constant cross-sectional area to maintain high-speed flow and ensure that the reagents and flue gas are fully and uniformly mixed.

[0012] 2) In the primary reactor, the reagent and flue gas are fully mixed and in contact. Most of the SO2, acidic gases, heavy metals, dioxins, etc. in the flue gas react with the reagent and are removed. The primary reactor is equipped with a flue gas distribution plate to ensure uniform gas distribution and increase the gas-solid mixing effect. Subsequently, the gas-solid mixture enters the cylindrical throat through the conical contraction section. After the flue gas and reagent are fully mixed again, they enter the secondary reactor through the diffusion section. The ratio of the diameter of the cylindrical throat to the diameter of the flue gas inlet pipe is 0.5-2:1, and the ratio of its length to the diameter of the flue gas inlet pipe is 0.5-2:1. After being mixed in the throat, the gas-solid mixture then enters the secondary reactor through the diffusion section. The ratio of the diameter of the cylinder in the secondary reactor to the diameter of the flue gas duct is 3-8:1. The secondary reactor is equipped with a flue gas distribution plate to ensure uniform gas-solid mixing and to distribute the gas evenly. In the secondary reactor, SO2, acidic gases and other substances in the flue gas are further removed. The gas-solid mixture then enters a baghouse dust collector, where dust, reaction products, and unreacted reagents are trapped and fall into the ash hopper as dust collector ash. The ash ash in the ash hopper contains unreacted reagents. To fully utilize resources, a portion of the dust collector ash is reused. Specifically, a portion of the dust collector ash is conveyed to a grinding feeder via a screw conveyor, ground to 200-1000 mesh, and then added to the diffusion section of the Venturi reactor. The proportion of reused dust collector ash is 30%–100% of the fresh reagent dosage. The addition of recycled dust improves reagent utilization, reduces reagent consumption, and lowers production costs. Furthermore, it increases the solid reagent content in the reactor, enhancing gas-solid mixing uniformity and the probability of contact reaction, thereby improving the removal efficiency of pollutants from flue gas. This process achieves SO2 removal rates ≥95%, HCl and HF removal rates ≥90%, heavy metal removal rates ≥80%, and dioxin removal rates ≥80%. As a dry process, it generates no wastewater or waste acid, avoiding the secondary pollution problems associated with wet processes. The flue gas requires no pre-treatment for cooling, and its post-reaction temperature is above the dew point, eliminating the need for secondary heating. This facilitates chimney exhaust diffusion and prevents the production of "white smoke." The process equipment is simple, requires a small footprint, and has low investment costs. The secondary reuse of dust collector ash not only improves the efficiency of pollutant removal but also greatly reduces operating costs. The unique reactor design achieves thorough gas-solid mixing and uniform reaction. At the same time, the reactor is flexible in setting up. Depending on the concentration of pollutants in the flue gas and the removal efficiency, it can be designed as a single-stage reactor or as a two-stage or multi-stage reactor.

[0013] 3) The primary and secondary reactors are equipped with flue gas distribution plates. The cross-sectional area of ​​the expansion section gradually recovers, the flow velocity decreases, and the gas is fully mixed through pressure difference. After the reagent and flue gas are fully and uniformly mixed in the Venturi reactor, they enter the primary reactor. The Venturi reactor is connected to the primary reactor. The ratio of the diameter of the cylinder in the primary reactor to the diameter of the flue gas inlet pipe is 3-8:1. The residence time of the flue gas in the two-stage reactor is 5-15 seconds. The reactor is equipped with flue gas distribution plates with a rhomboid structure to ensure uniform gas-solid mixing and to distribute the gas evenly. The technology has a wide range of applications, especially in operation at lower temperatures. It is suitable for treating flue gas containing corrosive components and has high flue gas pollutant removal efficiency: SO2 removal rate ≥95%, HCl and HF removal rate ≥90%, heavy metal removal rate ≥80%, and dioxin removal rate ≥80%. Attached Figure Description

[0014] Figure 1 This is an exploded perspective view of the overall structure of a preferred embodiment of a flue gas multi-pollutant synergistic treatment device according to the present invention.

[0015] In the diagram: 1. Flue gas inlet pipe; 2. Venturi reactor; 3. Reclaimed ash grinding and feeding machine; 4. Reagent storage silo; 5. Primary reactor; 6. Gas distribution plate; 7. Bag filter; 8. Ash hopper; 9. Ash silo; 10. Secondary reactor; 11. Screw conveyor; 12. Reclaimed ash grinding and feeding machine; 13. Purified flue gas outlet pipe; 14. Air guide pipe; 15. Throat pipe. Detailed Implementation

[0016] To enable those skilled in the art to understand the technical solution of this utility model more clearly, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings, but the implementation of this utility model is not limited thereto.

[0017] Example 1; as Figure 1 As shown, this embodiment provides a flue gas multi-pollutant synergistic treatment device, including a flue gas inlet pipe 1 for guiding gas, a Venturi reactor 2 installed at one end of the flue gas inlet pipe 1, a primary reactor 5 installed at the outer end of the Venturi reactor 2, a throat pipe 15 installed at the outer end of the primary reactor 5, a secondary reactor 10 connected to the outer end of the throat pipe 15, and a gas guide pipe 14 installed at the outer end of the secondary reactor 10. The outer end of the air duct 14 is connected to a bag filter 7, the bottom of the bag filter 7 is connected to a ash hopper 8, and the bottom of the ash hopper 8 is connected to an ash bin 9. One side of the ash hopper 8 is connected to a screw conveyor 11, and a grinding feeder 12 is installed on the screw conveyor 11. The grinding feeder 12 is connected to the Venturi reactor 2. The bag filter 7, ash hopper 8, screw conveyor 11 and grinding feeder 12 are cyclically connected to the Venturi reactor 2. The outer side of the bag filter 7 is connected to a purified flue gas outlet pipe 13; like Figure 1 As shown, the residence time of flue gas in the primary reactor 5 is 3-10 seconds. In the primary reactor 5, the reagent and flue gas are fully mixed and in contact. SO2, acidic gases, heavy metals, dioxins, etc. in the flue gas react fully with the reagent and are removed. Then, the gas-solid mixture passes through the conical contraction section and throat 15 and enters the secondary reactor 10. The flue gas and reagent are fully mixed again in throat 15 and then enter the secondary reactor 10 through the diffusion section. The ratio of the diameter of the cylindrical throat of the secondary reactor 10 to the diameter of the flue gas inlet pipe 1 is 0.5-2:1, and the ratio of its length to the diameter of the flue gas inlet pipe 1 is 0.5-2:1. After being mixed through the throat 15, the gas-solid mixture then enters the secondary reactor 10 through the diffusion section. The ratio of the diameter of the cylinder of the secondary reactor 10 to the diameter of the flue gas inlet pipe 1 is 3-8:1. The residence time of the flue gas in the secondary reactor 10 is 2-5 seconds. The secondary reactor 10 is equipped with a flue gas distribution plate 6 to ensure uniform gas-solid mixing and to distribute the gas evenly. In the secondary reactor 10, SO2, acidic gases and other substances in the flue gas are further removed. The gas-solid mixture then enters the bag filter 7, where dust, reaction products, and unreacted reagents are trapped and fall into the ash hopper 8 as dust collector ash. The dust collector ash in the ash hopper 8 contains unreacted reagents. In order to fully utilize resources, a portion of the dust collector ash is reused. Specifically, a portion of the dust collector ash is conveyed to the grinding feeder 12 by the screw conveyor 11, ground to 200-1000 mesh, and then added to the diffusion section of the Venturi reactor 2. The proportion of the reused dust collector ash is 30% to 100% of the amount of fresh reagent added. The addition of recycled dust improves reagent utilization, reduces reagent consumption, and lowers production costs. Furthermore, it increases the solid reagent content in the reactor, enhancing gas-solid mixing uniformity and the probability of contact reaction, thereby improving the removal efficiency of pollutants in the flue gas. This process can achieve SO2 removal rates ≥95%, HCl and HF removal rates ≥90%, heavy metal removal rates ≥80%, and dioxin removal rates ≥80%.

[0018] Example 2; The solution in Example 1 will be further described below with reference to its specific working method, as detailed in the following description: like Figure 1 As shown, in a preferred embodiment, based on the above method, the grinding and feeding assembly further comprises a grinding and feeding machine 3 and a reagent storage silo 4; A grinding feeder 3 is installed at the upper end of the flue gas inlet pipe 1 at the bottom of the Venturi reactor 2, and a reagent storage bin 4 is connected to the grinding feeder 3. like Figure 1 As shown, in a preferred embodiment, based on the above method, the flue gas is further injected into the Venturi reactor 2 through the flue gas inlet pipe 1. The reagents calcium hydroxide, sodium bicarbonate, and high specific surface area porous reaction material from the reagent storage silo are quantitatively added to the grinding feeder 3, ground to a certain particle size of 200-1000 mesh, and added into the flue gas inlet pipe 1, where they are vigorously mixed with the flue gas at a certain temperature of 120-300°C in the Venturi reactor 2. like Figure 1 As shown, in a preferred embodiment, based on the above method, the Venturi reactor 2 is further composed of four parts: an inlet cylindrical section, a conical constriction section, a cylindrical throat, and a diffuser section. The length of the inlet section is equal to the diameter of the flue gas inlet pipe 1, the angle of the conical constriction section is 18-25°, the ratio of the diameter of the throat to the diameter of the flue gas inlet pipe 1 is 0.3-0.5:1, the angle of the diffuser section is controlled at 6-16°, the cross-sectional area of ​​the constriction section gradually decreases, thereby increasing the gas flow rate, and the throat maintains a constant cross-sectional area to maintain high-speed flow.

[0019] Example 3; The solutions in Examples 1 and 2 will be further described below with reference to their specific working methods, as detailed in the following description: like Figure 1 As shown, in a preferred embodiment, based on the above method, further, flue gas distribution plates 6 are distributed in the primary reactor 5 and the secondary reactor 10 respectively, the cross-sectional area of ​​the expansion section is gradually restored, the flow velocity is reduced and the gas is fully mixed by pressure difference, the reagent and flue gas are fully and evenly mixed in the Venturi reactor 2 and then enter the primary reactor 5, the Venturi reactor 2 is connected to the primary reactor 5. like Figure 1 As shown, in a preferred embodiment, based on the above method, the ratio of the diameter of the cylinder of the primary reactor 5 to the diameter of the flue gas inlet pipe 1 is 3-8:1, the total residence time of the flue gas in the primary and secondary reactors is 5-15s, and a flue gas distribution plate 6 is provided inside the reactor. The flue gas distribution plate 6 has a rhomboid structure to ensure uniform gas-solid mixing and to play a role in uniform gas distribution.

[0020] The above description is only a further embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the scope disclosed by the present utility model, based on the technical solution and concept of the present utility model, shall fall within the protection scope of the present utility model.

Claims

1. A flue gas multi-pollutant synergistic treatment device, comprising a flue gas inlet pipe (1) for guiding gas, wherein a Venturi reactor (2) is installed at one end of the flue gas inlet pipe (1), a primary reactor (5) is installed at the outer end of the Venturi reactor (2), a throat pipe (15) and a secondary reactor (10) are installed at the outer end of the primary reactor (5), and a gas guide pipe (14) is installed at the outer end of the secondary reactor (10). Its features are: The outer end of the air duct (14) is connected to a bag filter (7), the bottom of the bag filter (7) is connected to a ash hopper (8), and the bottom of the ash hopper (8) is connected to an ash bin (9). The ash hopper (8) is connected to a screw conveyor (11) on one side. A recycled ash grinding and feeding machine (12) is installed on the screw conveyor (11). The recycled ash grinding and feeding machine (12) is connected to the diffusion section of the Venturi reactor (2). The bag filter (7), ash hopper (8), screw conveyor (11) and recycled ash grinding and feeding machine (12) are cyclically connected to the Venturi reactor (2). The outer side of the bag filter (7) is connected to a purified flue gas outlet pipe (13). A grinding and feeding assembly is installed at the upper end of the flue gas inlet pipe (1).

2. A device for the simultaneous treatment of multiple pollutants from flue gas according to claim 1, characterized in that: The primary reactor (5) and the secondary reactor (10) are respectively composed of a bottom diffuser cone bottom, a middle cylindrical body and an upper contraction cone top, and are equipped with a flue gas distribution plate (6) inside. The primary reactor (5) and the secondary reactor (10) are connected by a throat (15), and the residence time of the flue gas in the primary reactor (5) is 3-10s; The residence time of the flue gas in the secondary reactor (10) is 2-5 s.

3. A device for the simultaneous treatment of multiple pollutants from flue gas according to claim 1, characterized in that: The grinding and feeding assembly consists of a grinding and feeding machine (3) and a reagent storage bin (4); A grinding feeder (3) is installed at the upper end of the flue gas inlet pipe (1) at the bottom of the Venturi reactor (2), and a reagent storage silo (4) is connected to the grinding feeder (3).

4. A multi-pollutant synergetic treatment device of flue gas according to claim 3, characterized in that: The conical contraction section of the Venturi reactor (2) has an angle of 20-25°, the ratio of the throat diameter to the flue gas inlet pipe (1) diameter is 0.3-0.5:1, and the diffusion section angle is 10-15°.

5. A multi-pollutant co-processed flue gas treatment apparatus according to claim 4, wherein: The diameter of the cylindrical throat (15) between the primary reactor (5) and the secondary reactor (10) is 0.5-2:1, and its length is 0.5-2:

1. The diameter of the cylindrical body of the primary reactor (5) and the secondary reactor (10) is 3-8 times the diameter of the flue gas inlet pipe (1).

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