Sintering flue gas desulfurization, denitrification and dust removal integrated device

Abstract

The utility model provides a sintering flue gas desulfurization, denitrification and dust removal integrated device which comprises a primary dust removal unit, a desulfurization unit, a dust removal and denitrification unit and a flue gas discharge unit which are sequentially communicated through a flue gas pipeline, and further comprises an ozone supply unit, a temperature regulation and control unit and an ammonia escape treatment unit, the ozone supply unit is arranged between the primary dust removal unit and the desulfurization unit; the temperature regulation and control unit comprises a heat exchange part and a heating part, a heating section of the heat exchange part is arranged on the flue gas pipeline between the dust removal and denitration unit and the flue gas discharge unit, and a cooling section of the heat exchange part and the heating part are sequentially arranged on the flue gas pipeline between the desulfurization unit and the dust removal and denitration unit; the ammonia escape treatment unit is arranged at the upper box body of the dust removal and denitration unit and comprises an oxygen injection pipeline and a first CEMS analyzer, the oxygen injection pipeline is communicated with the upper box body and an external oxygen supply device and is arranged on one side, far away from the flue gas outlet, of the upper box body, and a probe sampling end of the first CEMS analyzer extends into the upper box body.

Description

Technical Field

[0001] This utility model belongs to the field of sintering flue gas treatment technology, and relates to a sintering flue gas treatment device, especially an integrated device for desulfurization, denitrification and dust removal of sintering flue gas. Background Technology

[0002] In the process of desulfurization, denitrification, and dust removal of sintering flue gas, it is necessary to provide a corresponding temperature window for the flue gas to carry out corresponding reactions such as desulfurization, denitrification, absorption of residual ammonia, and decomposition of excess ozone. Utility model patents with authorization announcement numbers CN214345083U, CN215085610U, CN215782173U, and CN215310886U respectively provide integrated devices for flue gas desulfurization, dust removal, and denitrification. These devices utilize different flue gas circulation or enrichment methods to desulfurize, denitrify, and remove dust from the sintering flue gas by combining an entrained flue gas reactor with a dust removal and denitrification unit, or by combining a desulfurization reaction device with a dust removal and denitrification unit.

[0003] However, during the application of the aforementioned devices and methods for desulfurization, denitrification, and dust removal of sintering flue gas, staff discovered that the desulfurization and denitrification efficiency often failed to meet expectations. Analysis revealed that this was because, during the desulfurization and denitrification processes using the aforementioned devices and methods, the flue gas temperature was not within the optimal temperature window for the reaction, leading to low reaction efficiency and even the generation of other byproducts. While the utility model patent with authorization announcement number CN215782173U incorporates a gas-to-gas heat exchanger and a high-temperature flue for high CO and NO content... x The flue gas in the flue undergoes heat exchange; however, the temperature range of sintering flue gas is generally between 120℃ and 180℃, while NO... x The rapid SCR reaction, normal SCR reaction, and the oxidative decomposition reaction of residual ammonia all occur at temperatures of 300℃-400℃. Heat exchange in high-temperature flues cannot effectively reduce high CO and NO levels. x The flue gas in the flue reaches the temperature window where the reaction occurs. In addition, after the flue gas is denitrified and dust removed, ammonia may occasionally escape from the flue gas. The existing technology mentioned above generally controls the amount of ammonia supplied to the dust removal and denitrification unit to reduce ammonia escape, but this operation is prone to causing insufficient denitrification and excessive nitrate content in the discharged flue gas.

[0004] Therefore, it is necessary to provide a device that can reduce ammonia escape during the desulfurization, denitrification and dust removal process using an entrained flue gas reactor combined with a dust removal and denitrification unit, and can reasonably control the flue gas temperature to ensure that the reaction proceeds fully under suitable temperature conditions. Utility Model Content

[0005] The purpose of this utility model is to provide an integrated device for desulfurization, denitrification and dust removal of sintering flue gas, so as to solve the technical problems in the existing technology, such as the desulfurization and denitrification efficiency not reaching the expected level, low reaction efficiency, many by-products, and easy ammonia escape.

[0006] To achieve the above objectives, the specific technical solution of this utility model is as follows:

[0007] An integrated device for desulfurization, denitrification and dust removal of sintering flue gas includes a primary dust removal unit, a desulfurization unit, a dust removal and denitrification unit and a flue gas discharge unit connected in sequence through a flue gas pipeline. It also includes an ozone supply unit, a temperature control unit and an ammonia escape treatment unit. The ozone supply unit is located between the primary dust removal unit and the desulfurization unit.

[0008] The temperature control unit includes a heat exchange section and a heating section. The heating section of the heat exchange section is located on the flue gas duct between the dust removal and denitrification unit and the flue gas discharge unit. The cooling section and the heating section of the heat exchange section are sequentially located on the flue gas duct between the desulfurization unit and the dust removal and denitrification unit.

[0009] The ammonia escape treatment unit is located in the upper chamber of the dust removal and denitrification unit, and includes an oxygen injection pipeline and a first CEMS analyzer. The oxygen injection pipeline connects the upper chamber and an external oxygen supply device and is located on the side of the upper chamber away from the flue gas outlet. The sampling end of the probe of the first CEMS analyzer extends into the upper chamber.

[0010] The ozone supply unit includes an ozone generator, a gas mixer, a dilution fan, and an ozone distributor. The ozone generator's inlet is connected to an external oxygen supply device, and its outlet is connected to the first inlet of the gas mixer. The dilution fan introduces external air and connects to the second inlet of the gas mixer. The gas mixer's outlet is connected to the ozone distributor, which is connected to the flue gas duct of the primary dust removal unit and the desulfurization unit.

[0011] A second CEMS analyzer is also installed on the flue gas duct between the ozone distributor and the primary dust removal unit.

[0012] The desulfurization unit includes an entrained flue gas reactor and a third CEMS analyzer. The entrained flue gas reactor has a first desulfurizing agent injection port on the side wall of the inlet end and a second desulfurizing agent injection port on the rear side of the first bend change point near the inlet end. The third CEMS analyzer is located on the front side of the first bend change point of the entrained flue gas reactor.

[0013] The heating section and cooling section of the heat exchange unit are connected by a heat exchange tube, and a circulating pump is installed on the heat exchange tube. The heating section includes a hot air furnace, which is located between the cooling section of the heat exchange unit and the dust removal and denitrification unit, and is connected to the flue gas pipeline through a pipeline.

[0014] An ammonia supply unit is also provided between the dust removal and denitrification unit and the desulfurization unit. The ammonia supply unit includes an ammonia generating mechanism and a first ammonia injection grid and a second ammonia injection grid connected to it by pipeline. The first ammonia injection grid is installed on the flue gas pipeline between the dust removal and denitrification unit and the heating unit. The second ammonia injection grid is installed inside the dust removal and denitrification unit. A fourth CEMS analyzer is also provided between the first ammonia injection grid and the dust removal and denitrification unit.

[0015] The flue gas exhaust unit includes an induced draft fan, a fifth CEMS analyzer, and a chimney, which are sequentially arranged on the flue gas duct. The induced draft fan is a variable frequency induced draft fan, and the chimney exhausts flue gas to the outside.

[0016] The beneficial effects of this utility model are as follows: This utility model provides an integrated device for desulfurization, denitrification and dust removal of sintering flue gas. By setting a temperature control unit, the temperature of the flue gas entering the dust removal and denitrification unit can be effectively controlled, so that the flue gas reaches the temperature window of 300℃-400℃ for SCR reaction and rapid SCR reaction before entering the dust removal and denitrification unit, thereby ensuring effective denitrification of the flue gas and ensuring denitrification efficiency.

[0017] This invention also utilizes a heat exchange section on the flue gas duct to exchange heat with the flue gas entering the dust removal and denitrification unit by using the temperature of the flue gas discharged from the dust removal and denitrification unit. This effectively utilizes the waste heat of the discharged flue gas and avoids heat waste.

[0018] The ammonia escape treatment unit can effectively monitor the gas composition in the upper chamber of the dust removal and denitrification unit. When the ammonia content is higher than the set value, oxygen is introduced into the upper chamber. By introducing oxygen and utilizing the temperature and catalyst environment of the dust removal and denitrification unit, the excess ammonia reacts with oxygen to generate nitrogen and water, reducing the probability of ammonia escape and thus preventing the exhaust gas from polluting the surrounding environment. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the main structure of this utility model.

[0020] The markings in the diagram are as follows: 1. Primary dust removal unit; 2. Dust removal and denitrification unit; 3. Heating section; 4. Cooling section; 5. Upper casing; 6. Oxygen injection pipeline; 7. First CEMS analyzer; 8. Ozone generator; 9. Gas mixer; 10. Ozone distributor; 11. Second CEMS analyzer; 12. Entrained flue gas reactor; 13. Third CEMS analyzer; 14. First desulfurizing agent injection inlet; 15. Second desulfurizing agent injection inlet; 16. Heat exchange tube; 17. Circulating pump; 18. Ammonia production mechanism; 19. First ammonia injection grid; 20. Second ammonia injection grid; 21. Fourth CEMS analyzer; 22. Exhaust fan; 23. Fifth CEMS analyzer; 24. Chimney; 25. Flue gas duct; 26. Dilution fan. Detailed Implementation

[0021] To better understand the purpose, structure, and function of this utility model, a more detailed description of this utility model is provided below with reference to the accompanying drawings.

[0022] like Figure 1 As shown, this utility model provides an integrated device for desulfurization, denitrification and dust removal of sintering flue gas, which includes a primary dust removal unit 1, a desulfurization unit, a dust removal and denitrification unit 2 and a flue gas discharge unit connected in sequence through a flue gas pipe 25. The above units together constitute the main body of the device. Based on this, the device in this embodiment also includes an ozone supply unit, a temperature control unit and an ammonia escape treatment unit.

[0023] The ozone supply unit is located between the primary dust removal unit 1 and the desulfurization unit, and is used to supply ozone to the flue gas before it enters the desulfurization unit. Since the temperature range of the flue gas after exiting the sintering machine is between 120℃ and 180℃, the temperature of the flue gas will decrease when it is transported to the desulfurization unit after dust removal. At a temperature below 200℃, ozone can effectively oxidize sulfur dioxide and nitrogen oxides, promote the generation of sulfur trioxide, which is more likely to react with the desulfurizing agent, and nitrogen dioxide, which can undergo a rapid SCR reaction with nitric oxide. This promotes the desulfurization unit to improve its desulfurization efficiency and denitrification effect, as well as the denitrification efficiency and denitrification effect of the dust removal and denitrification unit 2.

[0024] The temperature control unit is used to regulate the temperature of the flue gas entering the dust removal and denitrification unit, ensuring that the flue gas temperature is within the 300℃-400℃ range required for SCR and rapid SCR reactions. Specifically, in this embodiment, the temperature control unit includes a heat exchange section and a heating section. The heating section 3 of the heat exchange section is located on the flue gas duct 25 between the dust removal and denitrification unit 2 and the flue gas discharge unit. The cooling section 4 and the heating section of the heat exchange section are sequentially located on the flue gas duct 25 between the desulfurization unit and the dust removal and denitrification unit 2. The heating section 3 and the cooling section 4 of the heat exchange section are connected by a heat exchange tube 16. A circulating pump 17 is installed on the heat exchange tube 16. A heat exchange medium is injected into the heat exchange tube 16. Under the action of the circulating pump 17, the heat exchange medium circulates from the heating section 3 after exchanging heat with the high-temperature flue gas and then to the low-temperature section, where it exchanges heat with the low-temperature flue gas in the flue gas duct 25 between the desulfurization unit and the dust removal and denitrification unit 2. The heating section includes a hot air furnace, which is located between the cooling section 4 of the heat exchange section and the dust removal and denitrification unit 2, and is connected to the flue gas duct 25 through a pipeline.

[0025] When the heat exchange unit exchanges heat with the flue gas between the desulfurization unit and the dust removal and denitrification unit 2, and the flue gas temperature is still lower than the 300℃-400℃ temperature range required for SCR and fast SCR reactions, the hot blast furnace is started to heat and deliver high-temperature air into the flue gas duct 25. To further deliver high-temperature air into the flue gas duct 25, a combustion fan can also be installed at the hot blast furnace. The operator can set this up according to the actual situation; no specific limitations are made in this embodiment.

[0026] Furthermore, in this embodiment, the ammonia escape treatment unit is located in the upper chamber 5 of the dust removal and denitrification unit 2, including an oxygen injection pipe 6 and a first CEMS analyzer. The oxygen injection pipe 6 connects the upper chamber 5 and an external oxygen supply device, and is located on the side of the upper chamber 5 away from the flue gas outlet, for supplying oxygen to the dust removal and denitrification unit 2. The sampling end of the probe of the first CEMS analyzer 7 extends into the upper chamber 5. Since the flue gas flows from bottom to top in the dust removal and denitrification unit 2, when the first CEMS analyzer 7 detects that the ammonia concentration in the upper chamber 5 of the dust removal and denitrification unit 2 exceeds the normal value, it indicates that ammonia is about to escape. At this time, oxygen is injected into the upper chamber 5 through the oxygen injection pipe 6. Under the temperature environment of 300℃-400℃ in the upper chamber 5, ammonia can react rapidly with oxygen to generate nitrogen and water vapor. By using this method to treat the excess ammonia in the dust removal and denitrification unit 2, the excess ammonia caused by excessive ammonia during the denitrification process can be effectively avoided, thus ensuring the purity of the flue gas discharged from the device.

[0027] Furthermore, the ozone supply unit in this embodiment includes an ozone generator 8, a gas mixer 9, a dilution fan 26, and an ozone distributor 10. The ozone generator 8 has its inlet connected to an external oxygen supply device and its outlet connected to the first inlet of the gas mixer 9. The dilution fan 26 introduces external air and connects to the second inlet of the gas mixer 9. The outlet of the gas mixer 9 is connected to the ozone distributor 10. The ozone distributor 10 is connected to the flue gas duct 25 of the primary dust removal unit 1 and the desulfurization unit. At the same time, a second CEMS analyzer 11 is also installed on the flue gas duct 25 between the ozone distributor 10 and the primary dust removal unit 1.

[0028] In this embodiment, the second CEMS analyzer 11 is used to analyze the composition and content of the flue gas before it enters the desulfurization unit. This helps the operator control the ozone supply unit to introduce appropriate ozone into the flue gas duct 25 using the ozone distributor 10. The ozone oxidizes the sulfides and nitrogen oxides in the flue gas, producing some sulfur trioxide, which reacts more readily with the desulfurizing agent, and nitrogen dioxide, which can undergo a rapid SCR reaction with nitric oxide and ammonia, thus improving desulfurization and denitrification efficiency. Furthermore, since ozone only easily decomposes into oxygen at high temperatures of 200℃-300℃, the ozone distributor 10 is placed at the front end of the desulfurization unit in this embodiment. This allows for full utilization of ozone, increasing the contact and reaction time between ozone and sulfides and nitrogen oxides, thereby promoting the complete oxidation of sulfides and nitrogen oxides in the flue gas.

[0029] Furthermore, the desulfurization unit in this embodiment includes a flue gas entrainment reactor 12 and a third CEMS analyzer 13. A first desulfurizing agent injection inlet 14 is provided on the side wall of the inlet end of the flue gas entrainment reactor 12, and a second desulfurizing agent injection inlet 15 is provided on the rear side near the first bend at the inlet end. Desulfurizing agent is injected into the flue gas entrainment reactor 12 through the first desulfurizing agent injection inlet 14 and the second desulfurizing agent injection inlet 15. The third CEMS analyzer 13 is located on the front side of the first bend at the flue gas entrainment reactor 12 and is used to monitor the temperature, components and concentrations of the flue gas in the flue gas entrainment reactor 12, determine the composition and concentration of nitrogen oxides, and assist in adjusting the injection concentration and injection amount of ozone, as well as the injection amounts of the first and second desulfurizing agents.

[0030] Furthermore, an ammonia supply unit is also provided between the dust removal and denitrification unit 2 and the desulfurization unit for injecting ammonia into the flue gas to perform a denitrification reaction. Specifically, the ammonia supply unit includes an ammonia generating mechanism 18, and a first ammonia injection grille 19 and a second ammonia injection grille 20 connected to it via pipelines. A control device and valves are installed on the pipeline at the outlet of the ammonia generating mechanism 18 to control the ammonia injection rate of each branch. The first ammonia injection grille 19 is installed on the flue gas pipeline 25 between the dust removal and denitrification unit 2 and the heating section for preliminary denitrification of the flue gas after it has been heated. The second ammonia injection grille 20 is installed inside the dust removal and denitrification unit 2 for secondary denitrification of the flue gas. A fourth CEMS analyzer 21 is also provided between the first ammonia injection grille 19 and the dust removal and denitrification unit 2. The fourth CEMS analyzer 21 monitors the temperature of the flue gas after heating and the concentration of each component in the flue gas. This is used to assist the heat exchange unit in adjusting the circulation power of the circulating pump 17 and to assist the ammonia supply unit in adjusting the ammonia injection rate of the first ammonia injection grille 19 and the second ammonia injection grille 20.

[0031] Furthermore, the flue gas discharge unit includes an induced draft fan 22, a fifth CEMS analyzer 23, and a chimney 24, which are sequentially arranged on the flue gas duct 25. In order to ensure that the flue gas reacts fully in the dust removal and denitrification unit 2, the induced draft fan 22 is a variable frequency induced draft fan 22. The power of the induced draft fan 22 is dynamically adjusted according to the monitoring data of the fifth CEMS analyzer 23, and then the purified flue gas is discharged to the outside through the chimney 24.

[0032] It is understood that this utility model has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this utility model. Furthermore, under the teachings of this utility model, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of this utility model.

Claims

1. A sintering flue gas desulfurization and denitrification dust removal integrated device, comprising a first dust removal unit (1), a desulfurization unit, a dust removal and denitrification unit (2) and a flue gas discharge unit which are sequentially communicated through a flue gas pipeline (25), characterized in that: It also includes an ozone supply unit, a temperature control unit and an ammonia escape treatment unit, wherein the ozone supply unit is located between the primary dust removal unit (1) and the desulfurization unit; The temperature control unit includes a heat exchange section and a heating section. The heating section (3) of the heat exchange section is set on the flue gas pipe (25) between the dust removal and denitrification unit (2) and the flue gas discharge unit. The cooling section (4) and the heating section of the heat exchange section are set on the flue gas pipe (25) between the desulfurization unit and the dust removal and denitrification unit (2). The ammonia escape treatment unit is located in the upper chamber (5) of the dust removal and denitrification unit (2), including an oxygen injection pipeline (6) and a first CEMS analyzer. The oxygen injection pipeline (6) connects the upper chamber (5) and an external oxygen supply device and is located on the side of the upper chamber (5) away from the flue gas outlet. The sampling end of the probe of the first CEMS analyzer (7) extends into the upper chamber (5).

2. The sintering flue gas desulfurization, denitrification and dust removal integrated device according to claim 1, characterized in that: The ozone supply unit includes an ozone generator (8), a gas mixer (9), a dilution fan (26), and an ozone distributor (10). The air inlet of the ozone generator (8) is connected to an external oxygen supply device, and the air outlet is connected to the first air inlet of the gas mixer (9). The dilution fan (26) introduces external air and connects to the second air inlet of the gas mixer (9). The air outlet of the gas mixer (9) is connected to the ozone distributor (10). The ozone distributor (10) is connected to the flue gas duct (25) of the primary dust removal unit (1) and the desulfurization unit. A second CEMS analyzer (11) is also installed on the flue gas duct (25) between the ozone distributor (10) and the primary dust removal unit (1).

3. The integrated desulfurization, denitrification, and dust removal device for sintering flue gas according to claim 1, characterized in that: The desulfurization unit includes a flue gas entrainment reactor (12) and a third CEMS analyzer (13). The flue gas entrainment reactor (12) has a first desulfurizing agent injection inlet (14) on the side wall of the inlet end and a second desulfurizing agent injection inlet (15) on the rear side near the first bend of the inlet end. The third CEMS analyzer (13) is located on the front side of the first bend of the flue gas entrainment reactor (12).

4. The integrated desulfurization, denitrification, and dust removal device for sintering flue gas according to claim 1, characterized in that: The heating section (3) and cooling section (4) of the heat exchange unit are connected by a heat exchange tube (16). A circulating pump (17) is installed on the heat exchange tube (16). The heating unit includes a hot air furnace, which is located between the cooling section (4) of the heat exchange unit and the dust removal and denitrification unit (2) and is connected to the flue gas pipeline (25) through a pipeline.

5. The integrated desulfurization, denitrification, and dust removal device for sintering flue gas according to claim 1, characterized in that: An ammonia supply unit is also provided between the dust removal and denitrification unit (2) and the desulfurization unit. The ammonia supply unit includes an ammonia generating mechanism (18) and a first ammonia injection grille (19) and a second ammonia injection grille (20) connected to it by pipeline. The first ammonia injection grille (19) is installed on the flue gas pipeline (25) between the dust removal and denitrification unit (2) and the heating unit. The second ammonia injection grille (20) is installed inside the dust removal and denitrification unit (2). A fourth CEMS analyzer (21) is also provided between the first ammonia injection grille (19) and the dust removal and denitrification unit (2).

6. The integrated desulfurization, denitrification, and dust removal device for sintering flue gas according to claim 1, characterized in that: The flue gas exhaust unit includes an induced draft fan (22), a fifth CEMS analyzer (23), and a chimney (24) arranged sequentially on the flue gas duct (25). The induced draft fan (22) is a variable frequency induced draft fan (22), and the chimney (24) exhausts smoke to the outside.

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