Flue gas desulfurization recycling method, flue gas desulfurization system and application

Abstract

The invention belongs to the technical field of flue gas treatment, and particularly relates to a flue gas desulfurization recycling method, a flue gas desulfurization system and application. The flue gas desulfurization recycling method comprises the following steps: carrying out mixed reaction on flue gas subjected to coke discharge and dust removal and carrier gas containing a desulfurizing agent, and removing a mixed reaction product to obtain desulfurized flue gas; the carrier gas is the desulfurized flue gas, and the temperature of the desulfurized flue gas is 50 DEG C or above. The flue gas desulfurization system comprises a desulfurizer part, a decoking and dedusting part, a mixed reaction part and a desulfurization product separation part, the desulfurizer part, the decoking and dedusting part and the desulfurization product separation part are respectively connected with the mixed reaction part; and the desulfurization product separation part is connected with the desulfurizer part. According to the flue gas desulfurization recycling method, flue gas subjected to coke discharge and dust removal is mixed with a desulfurizing agent, the flue gas subjected to coke discharge and dust removal does not contain or contains a small amount of coke powder, the content of the coke powder in a product obtained after mixed reaction is only 20%-30%, the content of a desulfurization reaction product is 70%-80%, and most of the coke powder is separated from the desulfurization reaction product; the coke powder and the desulfurization reaction product are fully recycled; and the carrier gas of the desulfurizing agent is the desulfurized flue gas, so that the desulfurized flue gas is fully utilized, and the desulfurization cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of flue gas treatment, and in particular relates to a flue gas desulfurization resource utilization method, a flue gas desulfurization system and an application thereof. Background Art

[0002] Ultra-low emissions in the coking industry are being promoted in an all-round way, and the requirements for sulfur dioxide in the flue gas from coking are becoming more and more stringent. In order to ensure that the ultra-low emission requirements are met stably, a desulfurization system needs to be added in most cases. Considering that the temperature of the flue gas in the dust removal flue gas pipeline is generally between 70°C and 90°C, the current desulfurization of the flue gas from coking dust removal mainly adopts dry desulfurization with Ca(OH)2 as the desulfurizer. In the current process, air is used as the conveying gas source and is pressurized by a booster blower (such as a Roots blower) and then sprayed into the flue together with the Ca(OH)2 desulfurizer. The desulfurizer reacts with sulfur dioxide in the flue gas to remove sulfur dioxide from the flue gas.

[0003] In the existing coke oven coke flue gas desulfurization process, there are technical problems such as high energy consumption, low desulfurizer utilization rate, high operating cost, inability to effectively remove pollutants such as tar in the coke exhaust dust removal flue gas, and inability to fully utilize coke powder and desulfurization reaction products. For example, the patent application publication number is CN 111744324A, which discloses a coke oven coal loading and coke pushing flue gas desulfurization and dust removal process. The desulfurizer injection air source adopts the "ambient air + compressor" method, and the flue gas is not pre-dusted before desulfurization, but directly enters the bag filter. There are two problems: dust in the flue gas will adsorb the desulfurizer, affecting the utilization rate of the desulfurizer, resulting in an increase in the calcium-sulfur ratio and an increase in the desulfurizer consumption; more dust will also increase the wear of the bag filter bag, affecting the service life of the filter bag. A large amount of dust in the original flue gas is mixed with the desulfurization reaction products. The dust removal powder produced by the filter bag filtration has a high calcium content, which affects its high-value resource utilization. Due to the high calcium content, it cannot be used as high-value coke powder for blast furnace injection. Also, due to the high calcium content and ash content, the quality indicators such as the thermal performance of coke will be reduced. It cannot be used for coal blending and can only be used as a low-value fuel, and its utilization value is greatly reduced. In addition, in the prior art, the carrier gas of the desulfurizer is heated air (normal temperature air does not meet the desulfurization reaction temperature), which is mixed with the desulfurizer and then mixed with the flue gas, increasing the desulfurization cost and steps. Summary of the invention

[0004] To solve the above problems, the present invention provides a flue gas desulfurization resource utilization method, a flue gas desulfurization system and an application. The method uses desulfurized flue gas as a carrier gas and separates most of the coke powder from the desulfurization reaction products, so that the coke powder and the desulfurization reaction products can be fully utilized as resources.

[0005] The present invention is achieved through the following technical solutions:

[0006] In a first aspect, the present invention provides a flue gas desulfurization resource utilization method, comprising the following steps:

[0007] The flue gas after the de-dusting is mixed with the carrier gas containing the desulfurizing agent for reaction, and the mixed reaction product is removed to obtain the desulfurized flue gas;

[0008] The carrier gas is the desulfurized flue gas, and the temperature of the desulfurized flue gas is above 50°C.

[0009] The flue gas desulfurization resource utilization method provided by the present invention mixes the flue gas after coking and dust removal with a desulfurizer, and the flue gas after coking and dust removal contains no or a small amount of coke powder, so that the content of coke powder in the desulfurization product after the mixed reaction is only 20% to 30%, and the content of the desulfurization product is 70% to 80%, and the coke powder is separated from the desulfurization reaction product, so that both the coke powder and the desulfurization reaction product can be fully utilized as resources; the carrier gas of the desulfurizer is the flue gas after desulfurization, so the flue gas after desulfurization is fully utilized, and the desulfurization cost is reduced.

[0010] In some possible implementations, the flow rate of the carrier gas containing the desulfurizing agent is 20 m / s to 30 m / s.

[0011] In some possible implementations, the flue gas flow rate is above 17 m / s.

[0012] In some possible implementations, a mixing angle between the flue gas and the carrier gas is 120° to 165°.

[0013] In a second aspect, the present invention provides a flue gas desulfurization system for realizing the above-mentioned flue gas desulfurization resource utilization method, comprising:

[0014] Desulfurization agent section, decoking and dust removal section, mixing reaction section and desulfurization product separation section;

[0015] The desulfurizing agent section, the decoking and dust removing section, and the desulfurization product separation section are respectively connected to the mixing reaction section;

[0016] The desulfurization product separation part is connected to the desulfurization agent part;

[0017] The desulfurization product separation unit includes a dust collector, a dust removal booster fan, a pressure-stabilizing gas storage tank and an exhaust pipe;

[0018] The dust collector inlet end is connected to the mixing reaction part outlet end;

[0019] The outlet end of the dust collector is connected to the inlet end of the dust removal booster fan;

[0020] The outlet end of the dust removal booster fan is connected to the inlet end of the pressure-stabilizing gas storage tank and the exhaust pipe respectively;

[0021] The outlet end of the pressure-stabilizing gas storage tank is connected to the desulfurizing agent portion.

[0022] In the flue gas desulfurization system provided by the present invention, the outlet end of the dust removal and booster fan is respectively connected to the pressure-stabilizing gas storage tank and the exhaust pipe, so that the flue gas after desulfurization can partially or completely enter the desulfurizer part, so that the flue gas desulfurization system forms a closed-loop desulfurization, reducing the two links of the original desulfurization system, the Roots blower boosting and air heating, improving the stability of the desulfurization system operation (the fewer the links, the less likely the system is to have problems, and the more stable the operation), and making full use of the temperature of the flue gas, thereby reducing the energy consumption of the system operation. The decoking and dust removal part can remove coke powder in advance, reduce the adsorption of coke powder on the desulfurizer, make more desulfurizer contact with sulfur dioxide in the flue gas, and improve the utilization efficiency of the desulfurizer; and removing most of the coke powder in advance can reduce the wear of the coke powder on the desulfurization product separation part, and can also make the coke powder.

[0023] In some possible implementations, the desulfurizing agent unit includes a desulfurizing agent bin and a gas-material mixing device;

[0024] The inlet end of the gas-material mixing device is respectively connected to the outlet end of the pressure-stabilizing gas storage tank and the outlet end of the desulfurizing agent bin;

[0025] The outlet end of the pressure-stabilizing gas storage tank is also connected to the desulfurizing agent bin;

[0026] The outlet end of the gas-material mixing device is connected to the mixing reaction part.

[0027] In some possible implementations, the mixing reaction section includes a desulfurizing agent nozzle and a mixing reaction pipeline;

[0028] The desulfurizing agent spray pipe comprises a main pipe and at least three branch pipes branching from the main pipe;

[0029] The branch pipe is inserted through the wall of the mixed reaction pipe so that the nozzle of the branch pipe is located in the mixed reaction pipe;

[0030] One end of the mixed reaction pipeline is connected to the outlet end of the decoking and dust removal section, and the other end is connected to the desulfurization product separation section.

[0031] In some possible implementations, the angle between the branch pipe and the central axis of the mixed reaction pipeline in the direction away from the outlet end of the decoking and dust removal section is 15° to 60°.

[0032] In some possible implementations, the angle between the line connecting two adjacent ejection ports and the central axis of the mixed reaction pipeline is 55° to 75°.

[0033] In some possible implementations, the system further includes a first electric valve, a second electric valve, a third electric valve, and a fourth electric valve;

[0034] The first electric valve is located at the inlet end of the pressure-stabilizing gas storage tank;

[0035] The second electric valve is located between the inlet end of the gas-material mixing device and the pressure-stabilizing gas storage tank;

[0036] The third electric valve is located between the desulfurizing agent bin and the pressure-stabilizing gas storage tank;

[0037] The fourth electric valve is located at the outlet end of the gas-material mixing device.

[0038] In a third aspect, the present invention provides an application of the flue gas desulfurization system provided by the present invention in the field of flue gas treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present drawings or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present drawings. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0040] Figure 1 This is a schematic structural diagram of a flue gas desulfurization system according to an embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of the structure of the desulfurizer unit in an embodiment of the present invention;

[0042] Figure 3a This is a schematic diagram of the structure of the mixing reaction unit 3 in an embodiment of the present invention;

[0043] Figure 3b This is a schematic diagram of the cross-sectional structure of the mixing reaction unit 3 in an embodiment of the present invention;

[0044] Figure 3c Schematic diagram of the angle between the discharge direction of the desulfurizing agent outlet in the mixing reaction part 3 and the direction in which the central axis of the mixing reaction pipe 32 is away from the outlet end of the decoking and dust removal part in the embodiment of the present invention;

[0045] Figure 4 A schematic diagram of the structure of the nozzle shape of a flue gas desulfurization system in an embodiment of the present invention;

[0046] Figure 5 This is a schematic diagram of the structure of a flue gas desulfurization system in Example 1 of the present invention.

[0047] Description of reference numerals:

[0048] 1-desulfurizing agent part, 11-shell, 12-fluidizing plate, 13-vacuum pressure release valve, 14-gas-material mixing device;

[0049] 2-De-coking and dust removal section;

[0050] 3-mixing reaction part, 31-desulfurizing agent nozzle, 311-branch pipe, 32-mixing reaction pipeline;

[0051] 4-desulfurization product separation section, 41-dust collector, 42-dust removal booster fan, 43-pressure stabilizing gas storage tank, 44-exhaust pipe, 45-pressure sensor, 46-flow meter;

[0052] 5- first electric valve;

[0053] 6- Second electric valve;

[0054] 7- the third electric valve;

[0055] 8-Fourth electric valve.

[0056] The purpose, features and advantages of this figure will be further described in conjunction with the embodiments with reference to the accompanying drawings. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is described and illustrated in conjunction with the embodiments below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0058] Obviously, the following descriptions are only some examples or embodiments of the present invention, and for those of ordinary skill in the art, the present invention can also be applied to other similar scenarios without creative work. In addition, it can also be understood that although the efforts made in such a development process may be complex and lengthy, for those of ordinary skill in the art related to the contents disclosed in the present invention, some changes in design, manufacturing or production based on the technical contents disclosed in the present invention are just conventional technical means, and should not be understood as the contents disclosed in the present invention being insufficient.

[0059] However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of substantially the same structures may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the following description is provided for those skilled in the art to fully understand the present invention and is not intended to limit the subject matter described in the claims.

[0060] If not otherwise specified, all embodiments and optional embodiments of the present invention may be combined with each other to form a new technical solution, and all technical features and optional technical features of the present invention may be combined with each other to form a new technical solution.

[0061] The term "desulfurization reaction product" refers to a mixture of a compound generated by the reaction of a desulfurizer with sulfur dioxide in flue gas and the desulfurizer.

[0062] The term "desulfurization product" refers to a mixture containing a small amount of coke powder and desulfurization reaction products. (There is ambiguity, it is recommended to be modified to: The term "desulfurization product" refers to a mixture containing a desulfurization reaction product and a small amount of coke powder)

[0063] In the desulfurization process of coke oven flue gas, the following specific technical problems are common:

[0064] (1) High energy consumption: The desulfurization of flue gas from coke dust removal mainly adopts dry desulfurization with Ca(OH)2 as the desulfurizer. In the current process, air is used as the conveying gas source and is pressurized by a Roots blower, and then sprayed into the flue together with the Ca(OH)2 desulfurizer. However, the air temperature is often low, and the temperature is even lower in winter, far below the lower temperature limit of 50°C for Ca(OH)2 dry desulfurization. For this reason, after the air is pressurized by the Roots blower, it needs to be heated by an electric heater or other heating methods, which consumes a lot of energy. In winter, when the air humidity is high or in rainy weather, the energy consumption will be even higher. In addition, considering the backup, at least two Roots blowers need to be equipped, which will increase the construction capital investment, and the operating cost will also increase during the operation and maintenance of the Roots blower. At the same time, with the addition of the Roots blower conveying pressurization and air heating links, the stability of the desulfurization system operation has more uncertain factors. Once there is a problem with the Roots blower conveying pressurization or air heating link, it will directly affect the desulfurization effect of the system. To address these problems, an air duct can be connected to the outlet of the booster fan of the dust collector, and the air duct can be mixed with the desulfurizer and then sprayed into the raw flue gas after the coke dust removal, thereby replacing the Roots blower and air heater.

[0065] (2) The utilization rate of desulfurizer is low, which increases the operating cost: There is a lot of coke powder in the raw flue gas of the coke oven, and the coke powder has a large specific surface area, which will adsorb part of the desulfurizer, making it difficult for the adsorbed desulfurizer to fully contact with sulfur dioxide, which will reduce the utilization rate of the desulfurizer and increase the consumption of the desulfurizer under the condition of the same desulfurization effect. The higher the dust concentration in the raw flue gas of the coke oven, the greater the degree of this adverse effect.

[0066] (3) Most of the dust in the flue gas from the coke collector is coke powder, which is hard and easy to wear the dust collector box and bags, affecting the normal and standard operation of the dust collector.

[0067] (4) The flue gas from the coke removal contains pollutants such as tar. When it enters the bag filter, it will easily cause the bags to become hardened, increasing the resistance of the filter.

[0068] (5) The coke powder after de-dusting is mixed with the desulfurization reaction products (mainly calcium sulfate, calcium hydroxide, and calcium sulfite) in large quantities, which is not conducive to the subsequent treatment and resource utilization of the dust powder. The mixed dust powder cannot be used as high-value coke powder for blast furnace injection, and because of its high ash content, it cannot be used for coal blending. It can only be used as a low-value fuel, and its utilization value is greatly reduced.

[0069] (6) The desulfurizer is usually injected at a single point or double point, and the injection angle is unreasonable, which affects the mixing effect of the desulfurizer and the original flue gas, and ultimately affects the desulfurization effect.

[0070] In order to solve the above technical problems, the embodiments of the present invention provide a flue gas desulfurization resource utilization method, a flue gas desulfurization system and an application. The flue gas desulfurization resource utilization method can mix the flue gas after coking and dust removal with the desulfurizer, so that the flue gas after coking and dust removal contains no or a small amount of coke powder, so that the content of coke powder in the desulfurization product after the mixed reaction is only 20% to 30%, and the content of the desulfurization product is 70% to 80%, and the coke powder is separated from the desulfurization reaction product, so that both the coke powder and the desulfurization reaction product can be fully utilized as resources; the carrier gas of the desulfurizer is the flue gas after desulfurization, which makes full use of the flue gas after desulfurization and reduces the desulfurization cost. The flue gas desulfurization system is a system for realizing the flue gas desulfurization resource utilization method of the embodiment of the present invention. The outlet end of the dust removal booster fan is respectively connected to the pressure-stabilizing gas storage tank and the exhaust pipe, so that the flue gas after desulfurization can partially enter the desulfurizer part, so that the flue gas desulfurization system forms a closed-loop desulfurization system, reducing the two links of Roots blower boosting and air heating used in the current desulfurization system, improving the stability of the desulfurization system operation (the fewer links, the less likely the system is to have problems, and the more stable the operation), and making full use of the temperature of the flue gas, thereby reducing the system operation energy consumption.

[0071] The following is a detailed description of a flue gas desulfurization resource utilization method, a flue gas desulfurization system and applications in an embodiment of the present application.

[0072]

Flue gas desulfurization resource utilization method

[0073] A first aspect of an embodiment of the present invention provides a flue gas desulfurization resource utilization method, comprising the following steps:

[0074] S10. Mixing the flue gas after the desulfurization with a carrier gas containing a desulfurizing agent, removing the mixed reaction product, and obtaining the desulfurized flue gas;

[0075] The carrier gas is the flue gas after desulfurization, and the temperature of the flue gas after desulfurization is above 50°C.

[0076] The flue gas desulfurization resource utilization method provided in the embodiment of the present invention mixes the flue gas after coke removal and dust removal with a desulfurizer, and the flue gas after coke removal and dust removal contains no or a small amount of coke powder, so that the content of coke powder in the product after the mixed reaction is only 20% to 30%, and the content of the desulfurization reaction product is 70% to 80%, most of the coke powder is separated from the desulfurization reaction product, so that the coke powder and the desulfurization reaction product can be fully utilized as resources; the carrier gas of the desulfurizer is the flue gas after desulfurization, which makes full use of the flue gas after desulfurization, reduces the desulfurization cost, and reduces the desulfurization steps.

[0077] In some embodiments, in the above step S10, the method for removing coke and dust from flue gas includes: removing coke powder and dust from the original flue gas by using a cyclone dust collector 41. It should be noted that the cyclone dust collector 41 is an existing device and is not particularly limited in the embodiments of the present invention.

[0078] In some embodiments, in the above step S10, the desulfurizing agent includes at least one of Ca(OH)2, Mg(OH)2, and Na2CO3. In this case, the desulfurizing agent reacts chemically with sulfur dioxide in the flue gas after the coke removal and dust removal to achieve the removal and purification of sulfur dioxide in the flue gas.

[0079] In some embodiments, in the above step S10, the flue gas flow rate is above 17 m / s, preferably 17 m / s to 25 m / s. In this case, the flue gas has sufficient turbulence to allow the flue gas and the desulfurizer to be quickly and fully mixed, while avoiding solid deposition of the desulfurizer.

[0080] In some embodiments, in the above step S10, the carrier gas flow rate of the desulfurizer is 20m / s to 30m / s. In this case, the carrier gas has enough power to load the desulfurizer (to prevent the desulfurizer from being deposited) and fully mix with the flue gas, while maintaining the service life of the pipeline and equipment.

[0081] In some embodiments, in the above step S10, the mixing angle between the flue gas flow direction and the carrier gas flow direction is 120° to 165°. In this case, the flue gas flow direction is substantially opposite to the carrier gas flow direction, so that the relative speed of mixing is greater, thereby improving the mixing effect of the flue gas and the desulfurizer, and ultimately improving the desulfurization effect of the flue gas.

[0082]

Flue gas desulfurization system

[0083] A second aspect of the embodiment of the present invention provides a flue gas desulfurization system to implement the above-mentioned flue gas desulfurization resource utilization method, such as Figure 1 As shown, including:

[0084] Desulfurizing agent section 1, decoking and dust removal section 2, mixing reaction section 3 and desulfurization product separation section 4;

[0085] The desulfurizing agent section 1, the decoking and dust removing section 2, and the desulfurization product separation section 4 are respectively connected to the mixing reaction section 3;

[0086] The desulfurization product separation section 4 is connected to the desulfurization agent section 1;

[0087] The desulfurization product separation unit 4 includes a dust collector 41, a dust removal booster fan 42, a pressure-stabilizing gas storage tank 43 and an exhaust pipe 44; the inlet end of the dust collector 41 is connected to the outlet end of the mixing reaction unit 3;

[0088] The outlet end of the dust collector 41 is connected to the inlet end of the dust removal booster fan 42;

[0089] The outlet end of the dust removal booster fan 42 is connected to the inlet end of the pressure-stabilizing gas storage tank 43 and the exhaust pipe 44 respectively;

[0090] The outlet end of the pressure-stabilizing gas storage tank 43 is connected to the desulfurizing agent unit 1 .

[0091] The flue gas desulfurization system provided by the embodiment of the present invention adopts a pressure-stabilizing gas storage tank 43 to buffer the flow rate of the flue gas and stabilize the pressure of the flue gas; the dust removal booster fan 42 can pressurize and heat the flue gas, and the outlet end of the dust removal booster fan 42 is respectively connected to the pressure-stabilizing gas storage tank 43 and the exhaust pipe 44, so that the flue gas after desulfurization can partially or completely enter the desulfurizer part 1, so that the flue gas desulfurization system forms a closed-loop desulfurization, reducing the two links of the Roots blower pressurization and air heating of the original desulfurization system, improving the stability of the desulfurization system operation (the fewer the links, the less likely the system is to have problems, and the more stable the operation), and making full use of the temperature of the flue gas, thereby reducing the system operation energy consumption.

[0092] In some embodiments, the desulfurizing agent unit 1 includes a desulfurizing agent bin and a gas-material mixing device 14;

[0093] The inlet end of the gas-material mixing device 14 is connected to the outlet end of the pressure-stabilizing gas storage tank 43 and the outlet end of the desulfurizing agent bin respectively;

[0094] The outlet end of the pressure-stabilizing gas storage tank 43 is also connected to the desulfurizing agent bin;

[0095] The outlet end of the gas-material mixing device 14 is connected to the mixing reaction part 3 .

[0096] In the above-mentioned desulfurizer section 1, the desulfurizer bin is used to contain the desulfurizer, and the gas-material mixing device 14 is used to mix the carrier gas and the desulfurizer evenly; the outlet end of the pressure-stabilizing gas storage tank 43 is connected to the desulfurizer bin, which is used to pass part of the desulfurized flue gas, load the desulfurizer in the desulfurizer bin into the gas-material mixing device 14, and mix it with another part of the desulfurized flue gas, and then enter the mixing reaction section 3 through the outlet end of the gas-material mixing device 14. It should be noted that the gas-material mixing device 14 is a commonly used device in the art and is not particularly limited in the embodiments of the present invention.

[0097] In some embodiments, the desulfurizing agent bin includes a shell 11, a fluidizing plate 12, and a vacuum pressure release valve 13;

[0098] The fluidizing plate 12 is located at the lower part of the shell 11 and is connected to the pressure-stabilizing gas storage tank 43;

[0099] The vacuum pressure release valve 13 is located on the housing 11 .

[0100] In the above-mentioned desulfurizer bin, the fluidizing plate 12 is used to pass part of the desulfurized flue gas discharged from the pressure-stabilizing gas storage tank 43, so that the desulfurized flue gas carries the desulfurizer into the gas-material mixing device 14; the vacuum pressure release valve 13 is mainly used to adjust the pressure in the shell 11 to protect the desulfurizer bin: the desulfurizer bin is connected to the mixing reaction part 3, and then indirectly connected to the desulfurization product separation part 4, and the inlet of the dust collector 41 in the desulfurization product separation part 4 is negative pressure; and the inlet of the desulfurizer bin is connected to the pressure-stabilizing gas storage tank 43, and the gas storage tank is positive pressure. The use of the vacuum pressure release valve 13 can prevent the desulfurizer bin from being affected by excessive negative pressure and positive pressure, especially excessive negative pressure.

[0101] In some specific embodiments, there are at least two fluidizing plates 12. In this case, the desulfurized flue gas can enter the shell 11 from at least two directions, which promotes the desulfurizer to enter the gas-material mixing device 14.

[0102] In some embodiments, the decoking and dust removal section 2 includes a pre-dust removal device. In this case, the pre-dust removal device removes coke powder and dust in the flue gas, reduces the adsorption of coke powder on the desulfurizer, allows more desulfurizer to contact sulfur dioxide in the flue gas, and improves the utilization efficiency of the desulfurizer; the collected coke powder does not contain desulfurization products and can be directly used as blast furnace pulverized coal, which can realize the separate utilization of wastes, making the utilization simpler and more valuable.

[0103] In some embodiments, the pre-dust removal device is a cyclone dust collector 41 .

[0104] In some embodiments, the mixing reaction unit 3 includes a desulfurizing agent nozzle 31 and a mixing reaction pipeline 32;

[0105] The desulfurizing agent spray pipe 31 includes a main pipe and at least three branch pipes 311 branching from the main pipe;

[0106] The branch pipe 311 is inserted through the wall of the mixing reaction pipe 32 so that the nozzle of the branch pipe 311 is located in the mixing reaction pipe 32;

[0107] One end of the mixed reaction pipeline 32 is connected to the outlet end of the decoking and dust removal section 2 , and the other end is connected to the desulfurization product separation section 4 .

[0108] In some embodiments, Figure 3cAs shown, the angle α between the branch pipe 311 and the central axis of the mixing reaction pipe 32 away from the outlet end of the decoking and dust removal section 2 is 15° to 60°, preferably 30° to 45°.

[0109] In the above-mentioned mixing reaction section 3, the nozzle of the branch pipe 311 is located in the mixing reaction pipeline 32, and the nozzle sprays out a carrier gas containing a desulfurizer, which is mixed with the flue gas in the mixing reaction pipeline 32 for reaction to obtain a desulfurization product, and then the desulfurization product is removed by the desulfurization product separation section 4 to obtain a desulfurized flue gas; the angle α between the branch pipe 311 and the central axis of the mixing reaction pipeline 32 away from the outlet end of the decoking and dust removal section 2 is 15° to 60°. Under the premise of ensuring convenient construction, the injection direction of the desulfurizer is roughly opposite to the direction of the flue gas flow, so that the relative speed is larger, thereby improving the mixing effect of the flue gas and the desulfurizer, and finally improving the desulfurization effect of the flue gas.

[0110] In some embodiments, Figure 3b As shown, the angle γ between the line connecting two adjacent nozzles and the central axis of the mixing reaction pipe 32 is 55° to 75°, preferably 60°. Figure 4 As shown, the nozzle shape is trumpet-shaped (or conical), and the vertex angle β is 45° to 60°. In this case, the desulfurizer is scattered from the nozzle and can be evenly dispersed in the flue gas, thereby improving the mixing effect of the flue gas and the desulfurizer, thereby improving the desulfurization effect of the flue gas.

[0111] In some specific embodiments, the desulfurizing agent nozzle 31 includes a main pipe and three branch pipes 311 branching from the main pipe;

[0112] The plane formed by the three branch pipes 311 is perpendicular to the wall of the mixing reaction pipe 32;

[0113] The angle 2γ between the two spray outlets and the central axis of the mixing reaction pipe 32 is 120°;

[0114] The vertex angle β is 60°.

[0115] In this case, the desulfurizer is sprayed at 2γ+β / 2 (half of the 60° diffusion angle of the nozzle on one side) + β / 2 (half of the 60° diffusion angle of the other nozzle) = 180°, so that the desulfurizer injection direction is generally from top to bottom, just covering the entire cross-section of the pipeline); and the nozzle is in a trumpet shape (or cone shape), which can make the desulfurizer sprayed into the flue cover a larger cross-section of the flue gas pipeline, thereby improving the mixing efficiency and mixing effect of the desulfurizer and the flue gas, and ultimately improving the desulfurization effect of the flue gas.

[0116] In some embodiments, the dust collector 41 is a bag dust collector 41 .

[0117] In some embodiments, the desulfurization product separation unit 4 further includes a pressure sensor 45 and a flow meter 46;

[0118] The pressure sensor 45 is connected to the pressure-stabilizing gas storage tank 43, and the flow meter 46 is located at the outlet of the pressure-stabilizing gas storage tank 43. In this case, the pressure sensor 45 is used to monitor the pressure value of the pressure-stabilizing gas storage tank 43 in real time, so that the pressure in the pressure-stabilizing gas storage tank 43 is maintained within a specified range; the flow meter 46 is used to control the flow rate of the desulfurized flue gas in the pressure-stabilizing gas storage tank 43 entering the desulfurizer section 1. It should be noted that the pressure sensor 45 and the flow meter 46 are conventional devices in the art, and their models are not described in detail in the embodiments of the present invention.

[0119] In some embodiments, the flue gas desulfurization system further includes a first electric valve 5, a second electric valve 6, a third electric valve 7 and a fourth electric valve 8;

[0120] The first electric valve 5 is located at the inlet end of the pressure-stabilizing gas storage tank 43;

[0121] The second electric valve 6 is located between the inlet end of the gas-material mixing device 14 and the pressure-stabilizing gas storage tank 43;

[0122] The third electric valve 7 is located between the desulfurizing agent bin and the pressure-stabilizing gas storage tank 43;

[0123] The fourth electric valve 8 is located at the outlet end of the gas-material mixing device 14 .

[0124] In this case, the first electric valve 5 is the inlet electric valve of the pressure-stabilizing gas tank 43, which controls the flow rate of the desulfurized flue gas entering the pressure-stabilizing gas tank 43, so that the flue gas pressure in the pressure-stabilizing gas tank 43 is maintained at a stable level of 0.3MPa~0.5MPa; the second electric valve 6 is the inlet electric valve of the gas-material mixing device 14, which controls the desulfurized flue gas entering the gas-material mixing device 14; the third electric valve 7 is the air inlet electric valve of the fluidizing plate 12, which controls the desulfurized flue gas entering the desulfurizer bin; the fourth electric valve 8 is the outlet electric valve of the gas-material mixing device 14, which controls the flow rate of the carrier gas containing the desulfurizer entering the mixing reaction part 3; the first electric valve 5 and the fourth electric valve 8 jointly control the inlet flow rate and outlet flow rate of the desulfurized flue gas.

[0125] In some embodiments, the descorching and dust removal unit 2, the mixing reaction unit 3, the dust collector 41, the dust removal booster fan 42, the pressure-stabilizing gas storage tank 43 and the outer wall surfaces of the flue connected thereto are respectively insulated with insulation materials. In this case, the insulation can increase the flue gas temperature, thereby increasing the reactivity of the desulfurizer and sulfur dioxide. It should be noted that the specific material of the insulation material is conventional in the art and is not particularly limited in the embodiments of the present invention, but as an example, the insulation material is aluminum silicate.

[0126] In some embodiments, a desulfurization method of a flue gas desulfurization system provided by an embodiment of the present invention is provided, comprising the following steps:

[0127] S1. The dust removal booster fan 42 passes the desulfurized flue gas into the pressure-stabilizing gas storage tank 43 to maintain the pressure therein at 0.3MPa to 0.5MPa.

[0128] S2. The desulfurized flue gas in the pressure-stabilizing gas storage tank 43 enters the gas-material mixing device 14 through the second electric valve 6 and enters the desulfurizer bin through the third electric valve 7; the desulfurized flue gas entering the desulfurizer bin fluidizes the desulfurizer to obtain a fluidizing gas containing the desulfurizer and enters the gas-material mixing device 14, and is mixed with the desulfurized flue gas entering the gas-material mixing device 14 through the second electric valve 6 to obtain a carrier gas containing the desulfurizer.

[0129] S3. The original flue gas of the coke pushing and dedusting of the coke oven passes through a pre-dust removal device (cyclone dust collector 41) to obtain the flue gas after the coke pushing and dedusting and enters the mixing reaction part 3.

[0130] S4. The carrier gas containing the desulfurizing agent enters the mixing reaction section 3 through the control of the fourth electric valve 8, and is mixed and reacted with the flue gas after the decoking and dust removal in the mixing reaction section 3 to obtain the flue gas containing the desulfurization product.

[0131] S5. The flue gas containing desulfurization products is passed through the desulfurization product separation unit 4 to remove the desulfurization products and obtain desulfurized flue gas.

[0132] In the desulfurization method of the flue gas desulfurization system, step S1 stabilizes the pressure of the pressure-stabilizing gas storage tank 43 at 0.3MPa to 0.5MPa, thereby stabilizing the flow rate of the carrier gas containing the desulfurizer entering the mixed reaction part 3. Step S2 controls the opening of the second electric valve 6 and the third electric valve 7, and adjusts the flow rate of the desulfurized flue gas entering the desulfurizer bin and the gas-material mixing device 14, thereby controlling the content and flow rate of the desulfurizer in the carrier gas containing the desulfurizer entering the mixed reaction part 3. Step S3 pushes the coke to remove dust from the original flue gas through the pre-dust removal device to remove most of the coke powder and dust in the flue gas, which not only reduces the adsorption of the coke powder on the desulfurizer, but also allows more desulfurizers to contact sulfur dioxide in the flue gas, improves the utilization efficiency of the desulfurizer, and can also reduce the wear of the coke powder on the dust collector 41 box and the bag; in addition, the coke powder obtained can be directly used as blast furnace pulverized coal, which can realize the separate utilization of waste, and the utilization is simpler and the utilization value is higher. In step S4, the fourth electric valve 8 combines with the second electric valve 6 to control the flow rate of the carrier gas containing the desulfurizer entering the mixing reaction part 3 to prevent the desulfurizer from being deposited in the pipeline and blocking the pipeline, and to prevent excessive flow rate from increasing the wear of the pipeline and equipment and affecting their service life. In step S5, the flue gas containing the desulfurization product is removed from the desulfurization product separation part 4, and the removed desulfurization product has a high sulfate content and can be recycled.

[0133] In some embodiments, in the above step S1, the gas pressure in the pressure-stabilizing gas storage tank 43 is always maintained at 0.3MPa to 0.5MPa; when it is lower than 0.3MPa, the opening of the first electric valve 5 is increased; when it is higher than 0.5MPa, the opening of the first electric valve 5 is reduced. In this case, the pressure head of the dust-removing booster fan 42 in the embodiment of the present invention is 0.5MPa to 1.0MPa. The gas storage tank mainly has the functions of gas storage and buffering and stabilizing pressure. Because the particles of the highly active calcium hydroxide desulfurizer are not too large, the 325 mesh screening rate is greater than 90%. While ensuring that the desulfurizer particles can be stably in a fluidized state and can be mixed as quickly as possible in the gas-material mixing device 14, the pressure in the gas storage tank of 0.3MPa to 0.5MPa can meet the needs. Too high pressure also requires higher production and daily operation of the gas storage tank. Too low pressure will affect the fluidization and mixing of the desulfurizer. In addition, the height of the desulfurizer storage tank is generally not more than 10m. When the desulfurizer stacking density is 0.40g / mL~0.6g / mL, the pressure of 0.1MPa is greater than the pressure generated by the desulfurizer stacking 10m high, which can ensure that the fluidizing gas enters the desulfurizer bin smoothly. At the same time, the pressure loss and the desulfurizer fluidization and gas-material mixing effects can be balanced within the range of 0.3MPa~0.5MPa.

[0134] The main indicators of the existing high-activity calcium hydroxide desulfurizer are: 325 mesh screening rate greater than 90%, pore capacity greater than 0.2cm 3 ·g -1 , specific surface area 42m 2 / g, purity is 90% (the purchasing index requires no less than 90%, here we take 90%), bulk density is 0.40g / mL~0.6g / mL, which is smaller than the density of water.

[0135] In some embodiments, in the above step S1, because the coke pushing of the coke oven is a periodic intermittent operation, when pushing the coke, the dust removal booster fan 42 runs at high speed, at which time the operating frequency of the frequency converter of the dust removal booster fan 42 is 40Hz~50Hz, and the total pressure at the fan outlet is relatively high; when not pushing the coke, it runs at low speed, at which time the operating frequency of the frequency converter of the dust removal booster fan 42 is 15Hz~30Hz, and the total pressure at the fan outlet is relatively low.

[0136] In some embodiments, in the above step S2, the flow rate of the fluidizing gas is 15m / s to 20m / s. In this case, the desulfurizer is in a completely fluidized state to avoid deposition or uneven distribution on the pipe section, and also has the effect of further mixing.

[0137] Fluidizing gas refers to the mixed gas containing desulfurizer discharged from the outlet of the desulfurizer bin.

[0138] In some embodiments, in the above step S2, the flow rate of the carrier gas is 20m / s to 30m / s. In this case, the carrier gas has enough power to load the desulfurizer (to prevent the desulfurizer from depositing) and fully mix with the flue gas, while maintaining the service life of the pipeline and equipment.

[0139] The carrier gas is the mixed gas containing the desulfurizing agent which is discharged from the outlet of the gas-material mixing device 14 and enters the mixing reaction part 3 .

[0140] In some embodiments, in the above step S3, the temperature of the raw flue gas from the coke removal process is 70°C to 90°C.

[0141] In some embodiments, in the above step S3, the flue gas flow rate after the decoking and dust removal is above 17 m / s, and the flow rate is preferably 17 m / s to 25 m / s. In this case, the flue gas has sufficient turbulence to allow the flue gas and the desulfurizer to be quickly and fully mixed, while preventing the desulfurizer and other solids from being deposited in the mixed reaction pipe 32, causing blockage or reducing the service life of the mixed reaction pipe 32.

[0142] In some embodiments, in the above step S3, the flue gas after de-coking and dust removal stays in the mixing reaction unit 3 for more than 4 seconds.

[0143] In some embodiments, in the above step S4, the fourth electric valve 8 is closed when the coke is not pushed. In this case, the operation efficiency of the desulfurization system can be improved, unnecessary consumption of desulfurizer can be avoided, and the operation cost can be saved on the basis of the sulfur dioxide in the coke pushing dust removal flue gas meeting the standard; at the same time, it can also prevent excessive desulfurizer from being deposited in the mixing reaction part 3, affecting the desulfurization product composition and the service life of the mixing reaction part 3.

[0144]

application

[0145] A third aspect of the embodiments of the present invention provides an application of the flue gas desulfurization system provided by the embodiments of the present invention in the field of flue gas treatment.

[0146] The following is further described in conjunction with specific embodiments. The following parameters are used in the embodiments involved below:

[0147] The dust content in the original flue gas selected for the push coke dust removal is 3g / m 3 , sulfur dioxide is 200mg / m 3 ;

[0148] In the flue gas desulfurization system involved, the descorching and dust removal section 2, the mixing reaction section 3, the dust collector 41, the dust removal booster fan 42, the pressure-stabilizing gas storage tank 43 and the outer wall surfaces of the connected flue are respectively insulated with aluminum silicate;

[0149] The selected desulfurizer is calcium hydroxide, the molar ratio of calcium hydroxide to sulfur dioxide is 2:1, and the specific surface area of ​​calcium hydroxide is 42m 2 / g, purity is 90%;

[0150] When the coke pusher is running at high speed, the flue gas temperature in the flue is 80°C, and the outlet flue gas temperature of the dust removal booster fan 42 is 58°C;

[0151] Because coke pushing of the coke oven is a periodic intermittent operation, when pushing coke, the dust removal booster fan 42 runs at high speed. At this time, the operating frequency of the frequency converter of the dust removal booster fan 42 is 40Hz~50Hz, and the total pressure at the fan outlet is relatively high; when not pushing coke, it runs at low speed. At this time, the operating frequency of the frequency converter of the dust removal booster fan 42 is 15Hz~30Hz, and the total pressure at the fan outlet is relatively low.

[0152] Example 1

[0153] Example 1 provides a flue gas desulfurization resource recovery method, the steps are as follows:

[0154] S1-10. Use cyclone centrifugal method to remove coke powder and other particulate matter in the original flue gas of coke pushing and dust removal to obtain the flue gas after coke removal and dust removal.

[0155] S1-20. The flue gas after the coke removal and dust removal is mixed with the carrier gas containing the desulfurizer for reaction, wherein the flow rate of the flue gas after the coke removal and dust removal is 17m / s, the flow rate of the carrier gas containing calcium hydroxide is 25m / s, and the mixing angle between the flue gas flow direction and the carrier gas flow direction is 150°.

[0156] S1-30. Remove the mixed reaction product (ie, desulfurization product) to obtain desulfurized flue gas.

[0157] Example 2

[0158] Example 2 provides a flue gas desulfurization system, the structure of which is as follows:

[0159] Cyclone dust collector 41, desulfurizing agent nozzle 31, mixing reaction pipeline 32, dust collector 41, dust removal booster fan 42, pressure-stabilizing gas storage tank 43, pressure sensor 45, flow meter 46, desulfurizing agent bin, gas-material mixing device 14, first electric valve 5, second electric valve 6, third electric valve 7, fourth electric valve 8 and exhaust pipe 44;

[0160] The cyclone dust collector 41, the mixing reaction pipeline 32, the dust collector 41, the dust removal booster fan 42, the first electric valve 5, the pressure-stabilizing gas storage tank 43, the flow meter 46, the second electric valve 6, the gas-material mixing device 14, the desulfurizer nozzle 31 and the mixing reaction pipeline 32 are connected in a closed loop in sequence; the fluidizing plate 12 of the desulfurizer bin is connected to the outlet end of the pressure-stabilizing gas storage tank 43 through the third electric valve 7; the outlet end of the desulfurizer bin is connected to the inlet end of the gas-material mixing device 14, and the exhaust pipe 44 is connected to the outlet end of the dust removal booster fan 42; the pressure sensor 45 monitors the pressure in the pressure-stabilizing gas storage tank 43 in real time.

[0161] Among them, the desulfurizer nozzle 31 contains three branch pipes 311, and the angle α between the branch pipe 311 and the central axis of the mixed reaction pipeline 32 away from the outlet end of the decoking and dust removal section 2 is 30°; the angle between the nozzles of two adjacent branch pipes 311 and the connecting line of the central axis of the mixed reaction pipeline 32 is 60°.

[0162] A vacuum pressure release valve 13 is also provided on the shell 11 of the desulfurizing agent bin.

[0163] This embodiment also provides a desulfurization method for a flue gas desulfurization system, the steps are as follows:

[0164] S2-1. The dust removal booster fan 42 introduces the desulfurized flue gas into the pressure-stabilizing gas storage tank 43 to maintain the pressure therein at 0.4 MPa.

[0165] S2-2. The desulfurized flue gas in the pressure-stabilizing gas storage tank 43 enters the gas-material mixing device 14 through the second electric valve 6 and enters the desulfurizer bin through the third electric valve 7; the desulfurized flue gas entering the desulfurizer bin fluidizes the desulfurizer (i.e. calcium hydroxide, the same below) to obtain the fluidizing gas containing the desulfurizer and enters the gas-material mixing device 14, and is mixed with the desulfurized flue gas entering the gas-material mixing device 14 through the second electric valve 6 to obtain the carrier gas containing the desulfurizer; wherein, the flow rate of the fluidizing gas is 15m / s, and the flow rate of the carrier gas is 25m / s.

[0166] S2-3. The original flue gas from the coke oven is dedusted and the coke powder and dust are removed by the cyclone dust collector 41 to obtain the dedusted flue gas and enter the mixed reaction pipeline 32.

[0167] S2-4. The carrier gas containing the desulfurizer in the gas-material mixing device 14 is controlled by the fourth electric valve 8 to enter the mixing reaction section 3, and is mixed and reacted with the flue gas after the decoking and dust removal in the mixing reaction section 3 to obtain the flue gas containing the desulfurization product; wherein, the time that the flue gas after the decoking and dust removal stays in the mixing reaction pipe 32 is 5s and the flow rate is 20m / s.

[0168] S2-5. The flue gas containing desulfurization products is passed through the desulfurization product separation section 4 to remove the desulfurization products and obtain desulfurized flue gas.

[0169] Example 3

[0170] Embodiment 3 provides a flue gas desulfurization system, which has a structure basically the same as that of Embodiment 2, except that the angle between the discharge direction of the nozzle and the direction of the central axis of the mixing reaction pipeline 32 away from the outlet end of the cyclone dust collector 41 is 45°.

[0171] This comparative example also provides a desulfurization method for a flue gas desulfurization system, the steps of which are basically the same as those of Example 2, except that:

[0172] In step S2-2, the flow rate of the fluidizing gas is 20 m / s and the flow rate of the carrier gas is 30 m / s.

[0173] In step S2-4, the flue gas flow rate after the decoking and dust removal is 25 m / s.

[0174] Comparative Example 1

[0175] Comparative Example 1 provides a flue gas desulfurization system, which has a structure that is basically the same as that of Example 2, except that the dust removal booster fan 42 is replaced by a Roots blower and a heater located at the outlet of the Roots blower.

[0176] This comparative example also provides a desulfurization method for a flue gas desulfurization system, the steps of which are basically the same as those of Example 2, except that:

[0177] A Roots blower and a Roots blower outlet heater are used to heat the flue gas after desulfurization.

[0178] Comparative Example 2

[0179] Comparative Example 2 provides a flue gas desulfurization system, which has a structure that is basically the same as that of Example 2, except that it does not contain a cyclone dust collector 41.

[0180] This comparative example also provides a desulfurization method for a flue gas desulfurization system, the steps of which are basically the same as those of Example 2, except that:

[0181] Step S2-3 is not included, that is, the raw flue gas does not pass through the cyclone dust collector 41 to remove coke powder and dust, and directly enters the mixed reaction pipeline 32.

[0182] Comparative Example 3

[0183] Comparative Example 3 provides a flue gas desulfurization system, which has a structure basically the same as that of Example 2, except that: it does not contain the gas-material mixing device 14; the angle α between the branch pipe and the central axis of the mixing reaction pipeline 32 away from the outlet end of the cyclone dust collector 41 is 80°.

[0184] This comparative example also provides a desulfurization method for a flue gas desulfurization system, the steps of which are basically the same as those of Example 2, except that:

[0185] In step S2-2, the desulfurized flue gas in the pressure-stabilizing gas storage tank 43 enters the desulfurizer bin through the third electric valve 7, and the fluidizing gas containing the desulfurizer discharged from the outlet of the desulfurizer bin is directly mixed with the desulfurized flue gas passing through the second electric valve 6 in the pipeline to form a carrier gas containing the desulfurizer and enters the mixed reaction pipeline 32; wherein the flow rate of the fluidizing gas is 10 m / s and the flow rate of the carrier gas is 15 m / s.

[0186] Comparative Example 4

[0187] Comparative Example 4 provides a flue gas desulfurization system, the structure of which is the same as that of Example 2.

[0188] This comparative example also provides a desulfurization method for a flue gas desulfurization system, the steps of which are basically the same as those of Example 2, except that:

[0189] In step S2-4, the flue gas after de-coking and dust removal stays in the mixing reaction pipe 32 for 2 seconds.

[0190] In order to verify the progressiveness of a flue gas desulfurization resource utilization method and a flue gas desulfurization system provided in an embodiment of the present invention, the sulfur dioxide concentration in the flue gas before and after desulfurization, the char powder content in the desulfurization product and the content of the desulfurization reaction product (mainly sulfate) in the embodiments and the comparative examples were detected, and the flue gas desulfurization efficiency and the molar ratio (Ca / S) of calcium hydroxide (i.e., desulfurizer) and sulfur dioxide were calculated. The results are shown in Table 1 below.

[0191] Table 1

[0192]

[0193] From Table 1 above, at least the following conclusions can be drawn:

[0194] (1) The flue gas desulfurization resource utilization method provided in the embodiment of the present invention mixes the flue gas after coke removal and dust removal with the desulfurizer. The flue gas after coke removal and dust removal contains no or a small amount of coke powder, and most of the coke powder is separated from the desulfurization reaction products, so that the coke powder and the desulfurization reaction products can be more fully utilized as resources; the carrier gas of the desulfurizer is the flue gas after desulfurization, which makes full use of the flue gas after desulfurization, reduces the desulfurization cost, and reduces the number of desulfurization steps.

[0195] (2) The flue gas desulfurization system provided in the embodiment of the present invention adopts a pressure-stabilizing gas storage tank 43 to buffer the flow rate of the flue gas and stabilize the pressure of the flue gas; the dust removal and booster fan 42 can pressurize and heat the flue gas, and the outlet end of the dust removal and booster fan 42 is respectively connected to the pressure-stabilizing gas storage tank 43 and the exhaust pipe 44, so that the flue gas after desulfurization can partially enter the desulfurizer part 1, so that the flue gas desulfurization system forms a closed-loop desulfurization, reducing the two links of the original desulfurization system, namely, the Roots blower pressurization and air heating, thereby improving the stability of the desulfurization system operation (the fewer the links, the less likely the system is to have problems, and the more stable the operation), and making full use of the temperature of the flue gas, thereby reducing the system operation energy consumption.

[0196] (3) In the flue gas desulfurization system provided by the embodiment of the present invention, the angle between the branch pipe 311 and the central axis of the mixing reaction pipe 32 away from the outlet end of the decoking and dust removal section 2 is 30° to 45°, so that the injection direction of the desulfurizer and the flue gas flow direction can be roughly opposite, thereby making the relative speed larger, thereby improving the mixing effect of the flue gas and the desulfurizer, and ultimately improving the desulfurization effect of the flue gas.

[0197] (4) In the flue gas desulfurization system provided in the embodiment of the present invention, the pressure-stabilizing gas storage tank 43 can buffer the flow rate of the flue gas and stabilize the pressure of the flue gas, thereby stabilizing the flow rate of the carrier gas containing the desulfurizer entering the mixed reaction pipeline 32 at 20m / s to 30m / s. Under the premise that the pipeline and equipment maintain their service life, the carrier gas has sufficient power to load the desulfurizer (to prevent the desulfurizer from depositing) and fully mix with the flue gas, thereby improving the desulfurization efficiency.

[0198] (5) The flue gas desulfurization system provided in the embodiment of the present invention is provided with a pre-dust removal device (cyclone dust collector 41) before the desulfurization of the original flue gas, so as to remove most of the coke powder in advance, reduce the adsorption of the coke powder on the desulfurizer, and improve the desulfurization efficiency and the utilization rate of the desulfurizer.

[0199] (6) The desulfurization method of the flue gas desulfurization system provided by the embodiment of the present invention controls the pressure of the flue gas after desulfurization in the pressure-stabilizing gas storage tank 43, controls the flow of the fluidizing gas, the carrier gas, and the flue gas, and synergistically realizes the separation of the coke powder and the desulfurization reaction product, so that the coke powder and the desulfurization reaction product are recycled. At the same time, the flue gas after desulfurization is used as the carrier gas, and the temperature of the flue gas is fully utilized, thereby reducing the energy consumption of the system operation, and further reducing the desulfurization cost.

[0200] It should be noted that the present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and embodiments having substantially the same structure as the technical idea and exerting the same effects within the scope of the technical solution of the present invention are all included in the technical scope of the present invention. In addition, within the scope of the main purpose of the present invention, various modifications that can be thought of by those skilled in the art to the embodiments, and other methods of combining some of the constituent elements in the embodiments to construct are also included in the scope of the present invention.

Claims

1. A flue gas desulfurization resource recovery method, characterized in that: The steps include: The flue gas after the de-dusting is mixed with the carrier gas containing the desulfurizing agent for reaction, and the mixed reaction product is removed to obtain the desulfurized flue gas; The carrier gas is the desulfurized flue gas, and the temperature of the desulfurized flue gas is above 50°C.

2. The flue gas desulfurization resource recovery method according to claim 1, characterized in that: The carrier gas velocity containing the desulfurizing agent is 20m / s to 30m / s; And / or, the flue gas flow rate is above 17 m / s.

3. The flue gas desulfurization resource recovery method according to claim 1 or 2, characterized in that: The mixing angle between the flue gas and the carrier gas is 120° to 165°.

4. A flue gas desulfurization system, characterized in that: include: Desulfurization agent section, decoking and dust removal section, mixing reaction section and desulfurization product separation section; The desulfurizing agent section, the decoking and dust removing section, and the desulfurization product separation section are respectively connected to the mixing reaction section; The desulfurization product separation part is connected to the desulfurization agent part; The desulfurization product separation unit includes a dust collector, a dust removal booster fan, a pressure-stabilizing gas storage tank and an exhaust pipe; The dust collector inlet end is connected to the mixing reaction part outlet end; The outlet end of the dust collector is connected to the inlet end of the dust removal booster fan; The outlet end of the dust removal booster fan is connected to the inlet end of the pressure-stabilizing gas storage tank and the exhaust pipe respectively; The outlet end of the pressure-stabilizing gas storage tank is connected to the desulfurizing agent portion.

5. The flue gas desulfurization system according to claim 4, characterized in that: The desulfurizing agent section includes a desulfurizing agent bin and a gas-material mixing device; The inlet end of the gas-material mixing device is respectively connected to the outlet end of the pressure-stabilizing gas storage tank and the outlet end of the desulfurizing agent bin; The outlet end of the pressure-stabilizing gas storage tank is also connected to the desulfurizing agent bin; The outlet end of the gas-material mixing device is connected to the mixing reaction part.

6. The flue gas desulfurization system according to claim 4 or 5, characterized in that: The mixing reaction part includes a desulfurizing agent nozzle and a mixing reaction pipeline; The desulfurizing agent spray pipe comprises a main pipe and at least three branch pipes branching from the main pipe; The branch pipe is inserted through the wall of the mixed reaction pipe so that the nozzle of the branch pipe is located in the mixed reaction pipe; One end of the mixed reaction pipeline is connected to the outlet end of the decoking and dust removal section, and the other end is connected to the desulfurization product separation section.

7. The flue gas desulfurization system according to claim 6, characterized in that: The angle between the branch pipe and the central axis of the mixed reaction pipeline in the direction away from the outlet end of the decoking and dust removal section is 15° to 60°.

8. The flue gas desulfurization system according to claim 6 or 7, characterized in that: The angle between the line connecting two adjacent spray outlets and the central axis of the mixed reaction pipeline is 55° to 75°.

9. The flue gas desulfurization system according to any one of claims 5 to 8, characterized in that: The system further includes a first electric valve, a second electric valve, a third electric valve and a fourth electric valve; The first electric valve is located at the inlet end of the pressure-stabilizing gas storage tank; The second electric valve is located between the inlet end of the gas-material mixing device and the pressure-stabilizing gas storage tank; The third electric valve is located between the desulfurizing agent bin and the pressure-stabilizing gas storage tank; The fourth electric valve is located at the outlet end of the gas-material mixing device.

10. Use of the flue gas desulfurization system according to any one of claims 4 to 9 in the field of flue gas treatment.

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