Cooperative treatment system for multiple pollutants in sintering flue gas

Abstract

The invention relates to a flue gas purification technology, and particularly discloses a sintering flue gas multi-pollutant co-processing system, the sintering flue gas multi-pollutant co-processing system comprises an MGGH, a desulfurization device, a GGH, a heating device, a CO removal device and an SCR denitration device, the MGGH comprises an MGGH low temperature section and an MGGH high temperature section, the MGGH low-temperature section, the desulfurization device, the CO removal device, the SCR denitration device and the MGGH high-temperature section are sequentially connected through pipelines in the flue gas flowing direction; the heating device is used for heating to-be-treated flue gas at the gas inlet of the CO removal device. The sintering flue gas multi-pollutant cooperative treatment system has the advantages of full utilization of waste heat and stable system operation.

Description

Technical Field

[0001] The present application relates to industrial flue gas purification technology, and in particular to a sintering flue gas multi-pollutant coordinated treatment system. Background Art

[0002] The amount of flue gas emitted during the steel sintering production process is large and contains many types of pollutants. 2 、NO x The emissions account for more than 70% of the total emissions of the plant, and also contain a large amount of SO 3 , HCl, HF, heavy metals and dioxins, and carbon monoxide emissions account for about 70% of the entire steel plant. Sintering flue gas contains about 1-2% CO (about 8000-20000mg / m 3 ), has become one of the pollutants in sintering flue gas that urgently needs to be treated. According to relevant data, about 1 / 4 of C in the sintering process is eventually emitted in the form of incomplete combustion, which causes about 15-20% of the energy to be emitted in the form of CO in the sintering flue gas, resulting in huge energy waste. At present, the reduction of CO emissions from sintering machine flue gas in the steel industry is mainly achieved through the recirculation of sintering machine flue gas, but the emission reduction effect is relatively limited, because excessive recirculation of sintering flue gas will reduce the output of the sintering machine and the quality of sintered ore.

[0003] With the introduction of relevant requirements for CO emission indicators in various regions, it is no longer possible to meet emission requirements by relying solely on front-end CO treatment, and it is necessary to add back-end CO treatment processes. For back-end CO treatment processes, catalytic oxidation methods are generally used to oxidize CO into CO 2 At present, the CO catalysts with relatively good effects are mainly precious metal catalysts. However, precious metal catalysts are easily affected by flue gas SO 2 、SO 3 NH 3 The influence of other pollutants such as CO, CO2 and CO2 is easy to deactivate, the service life of the catalyst is short, and the CO removal system is unstable. Therefore, the CO removal process cannot simply consider the activity of the catalyst, but also needs to meet the synergistic removal of other pollutants, especially the SO in the flue gas at the front end of the CO catalyst. 2 、SO 3 Removal of acidic gases such as HCL.

[0004] At present, CO treatment at the back end of sintering flue gas needs to be combined with the existing desulfurization and denitrification technology. The flue gas desulfurization device sprays water into the absorption tower to wet the particle surface, creating good ion reaction conditions for flue gas desulfurization. The greater the amount of water sprayed, the more thorough the desulfurization reaction and the lower the amount of absorbent consumed. In order to avoid agglomeration in the absorption tower, the flue gas temperature in the desulfurization is generally not less than 80°C. Therefore, due to the flue gas temperature at the desulfurization inlet, the amount of water sprayed for desulfurization is small, resulting in a high desulfurization calcium-sulfur ratio.

[0005] Existing related technologies disclose a system and method for removing CO from sintering flue gas, including a semi-dry desulfurization reactor, a GGH heat exchanger, a hot blast furnace, an SCR reactor, and a precious metal catalytic oxidation reactor. After the sintering flue gas passes through the semi-dry desulfurization device, the flue gas at 80-90°C is first heated by the GGH heat exchanger, and then, under the action of the precious metal CO catalyst, CO is removed while the flue gas is heated by the heat released by the CO reaction. The heated flue gas passes through the heat exchanger to generate steam, which is merged into the steam network, and then enters the SCR reactor for denitrification. The catalytic reactor is arranged before the heating furnace, and the catalytic temperature of the catalyst needs to be at least 200°C. Although the system can be heated by a hot blast furnace, the GGH heat exchange process is slow, and the time required to raise the temperature to the CO reaction is relatively long. Although the precious metal CO catalyst is highly active, it is easily affected by flue gas SO 2 , dust and other pollutants, and are easily inactivated, so the system stability needs to be improved.

[0006] The related technology discloses a method for removing NO from sintering flue gas CO x The method includes a dust removal and desulfurization system, a high-temperature hot blast furnace, a GGH heat exchanger, a denitrification tower, etc. The high-temperature flue gas at the sintering outlet is used for heat exchange with the flue gas at the desulfurization outlet and then enters the desulfurization tower for desulfurization, and then is mixed with the high-temperature air at the hot blast furnace outlet and then enters the denitrification tower to complete NO x The flue gas is then discharged from the chimney after heat exchange. This technology still requires a hot blast furnace to provide high-temperature flue gas to mix with the desulfurized flue gas, which does not fully utilize the heat of CO and has a high operating cost. Summary of the invention

[0007] In order to solve at least one of the above-mentioned problems of failure to fully utilize the heat released by catalytic oxidation of CO, high operating costs and poor system stability, the present application provides a sintering flue gas multi-pollutant coordinated treatment system.

[0008] The present application provides a sintering flue gas multi-pollutant coordinated treatment system, which adopts the following technical solutions:

[0009] A sintering flue gas multi-pollutant coordinated treatment system comprises an MGGH, a desulfurization device, a GGH, a heating device, a CO removal device and an SCR denitrification device, wherein the MGGH comprises an MGGH low-temperature section and an MGGH high-temperature section, wherein the MGGH low-temperature section, the desulfurization device, the CO removal device, the SCR denitrification device and the MGGH high-temperature section are respectively connected by pipelines in sequence along the flue gas flow direction; the heating device is used to heat the flue gas to be treated at the air inlet of the CO removal device; the original flue gas inlet of the GGH is connected to the air outlet of the desulfurization device, the original flue gas outlet of the GGH is connected to the air inlet of the CO removal device, and the clean flue gas inlet of the GGH is connected to the air outlet of the MGGH high-temperature section; the MGGH low-temperature section is interlocked with the MGGH high-temperature section, and the MGGH high-temperature section uses the high-temperature flue gas to heat heat medium water and cool the flue gas at the same time; the MGGH low-temperature section uses the heated heat medium water to heat the flue gas to be treated and cool the heat medium water at the same time.

[0010] By adopting the above technical scheme and the coordinated design of the MGGH and GGH, after the flue gas to be treated enters the sintering flue gas multi-pollutant coordinated treatment system of the present application, it flows through the MGGH low-temperature section and the desulfurization device in sequence, and the flue gas to be treated is heated in the MGGH low-temperature section (the heat comes from the heat exchange of the MGGH high-temperature section at the outlet of the denitrification device), and then enters the CO removal device through the original flue gas inlet of GGH and the original flue gas outlet of GGH in sequence. The flue gas is heated by heat exchange through GGH, which can reduce the denitrification heating end difference, and then flows through the CO removal device. The flue gas temperature is heated due to the heat released by the catalytic oxidation reaction of CO, and then flows out through the SCR denitrification device to form high-temperature flue gas. The high-temperature flue gas passes through the MGGH high-temperature section. Since the MGGH low-temperature section is linked with the MGGH high-temperature section, the MGGH high-temperature section uses the high-temperature flue gas to heat the heat medium water and cool the flue gas at the same time, and the MGGH low-temperature section arranged before the air inlet of the desulfurization device uses the heated heat medium water to heat the flue gas to be treated and cool the heat medium water at the same time. The flue gas to be treated is heated before entering the desulfurization device, that is, the temperature of the flue gas to be treated entering the desulfurization device is increased, which is conducive to the removal of SO 3 , HCL, HF and other strong acid pollutants. At the same time, increasing the temperature can increase the amount of water sprayed at the rear end and promote the removal of SO 2 Fully react with the absorbent to improve desulfurization efficiency, reduce calcium-sulfur ratio, reduce absorbent consumption, and reduce operating costs.

[0011] At the same time, the outlet of the high temperature section of MGGH is connected to the clean flue gas inlet of GGH. Therefore, the high temperature flue gas formed after flowing through the SCR denitrification device, in addition to a part of the flue gas heat being exchanged to the flue gas to be treated entering the desulfurization device through the low temperature section of MGGH and the high temperature section of MGGH, the other part of the flue gas flows into GGH from the clean flue gas inlet of GGH for heat exchange, that is, heat exchange to the flue gas entering the CO removal device. The heat released by the catalytic oxidation of CO can be fully utilized. MGGH is added after the denitrification device to reduce the flue gas temperature entering GGH and avoid GGH jamming. The overall stability of the system is good.

[0012] Preferably, it further comprises a dust removal device, the air inlet of the dust removal device is connected to the air outlet of the desulfurization device, and the air outlet of the dust removal device is connected to the original flue gas inlet of the GGH.

[0013] By adopting the above technical solution, as a specific structural example, adding a dust removal device can purify the dust in the flue gas after desulfurization, thereby preventing the dust from entering the CO removal device and causing catalyst deactivation. At the same time, it can also ensure that the entire system operates more stably.

[0014] Preferably, it also includes a bypass flue and a regulating valve, wherein the two ends of the bypass flue are connected to the air inlet of the CO removal device and the air outlet of the CO removal device respectively, and the regulating valve is respectively provided on the bypass flue, the air inlet pipe of the CO removal device, and the air outlet pipe of the CO removal device.

[0015] By adopting the above technical solution, as a specific structural example, the above bypass flue and regulating valve are designed. The temperature entering the SCR denitrification device and the GGH heat exchanger can be controlled by the regulating valves on the bypass flue, the air inlet pipe of the CO removal device, and the air outlet pipe of the CO removal device. When the CO concentration of the sintering flue gas changes, the system can still operate at the designed temperature.

[0016] Preferably, the heating device is a direct-fired furnace with a built-in flue, and the built-in flue of the heating device is respectively connected to the original flue gas inlet of the GGH and the air inlet of the CO removal device.

[0017] By adopting the above technical solution, as a structural example, in order to control the impact of changes in CO concentration in the flue gas on the system flue gas temperature, a heating device is provided to supplement the flue gas with heat when the machine is started and the CO concentration is not high.

[0018] The CO removal device is arranged at the air inlet of the SCR denitrification device. In the initial stage of operation, the flue gas can be heated by the heating device to meet the operating temperature requirement of the CO catalyst above 200°C. After stable operation, the flue gas can be heated only by the heat released by catalytic oxidation in the CO removal device, and the temperature rise of the flue gas can be adjusted by the regulating valve on the bypass flue of the CO removal device, and the heating device is gradually phased out. The heating device adopts a direct-fired furnace with a built-in flue. The switching of the heating device only requires stopping the gas supply, and the start-stop switching is convenient.

[0019] Preferably, it further comprises an air-inducing device and a chimney, the clean smoke outlet of the GGH is communicated with the air inlet of the air-inducing device, and the air outlet of the air-inducing device is connected with the chimney pipe.

[0020] By adopting the above technical solution, as a structural example, the flue gas after heat exchange by the GGH is discharged to the outside by using the induced draft device and the chimney. The induced draft device can adopt an existing induced draft fan that meets the functional parameter requirements.

[0021] Preferably, the desulfurization device is a circulating fluidized bed absorber, and the GGH is a rotary GGH.

[0022] Preferably, the catalyst in the CO removal device is a precious metal catalyst.

[0023] By adopting the above technical solution, as a structural example, a circulating fluidized bed semi-dry desulfurization is adopted, and a CO removal device and an SCR denitrification device using precious metal catalysts are connected. In addition, the coupling integration of the front and rear systems is considered, and a set of MGGH devices is set to transfer part of the heat of the high-temperature flue gas catalytically oxidized by CO to the desulfurization inlet for heating the flue gas at the inlet of the desulfurization device. Relying on a circulating fluidized bed absorption tower with high turbulence, high density, and two-stage high-efficiency reaction, the high-temperature section can remove strong acids (SO 3 , HCl, HF), and the low temperature section after water spraying removes SO 2 , can stably achieve SO 2 、SO 3 , HCl, HF, heavy metal mercury and fine dust and other pollutants are removed, while CO is efficiently removed, the optimal economic operation of the multi-pollutant removal device is achieved, that is, emission reduction and carbon reduction.

[0024] In summary, this application has at least the following beneficial effects:

[0025] (1) In the sintering flue gas multi-pollutant coordinated treatment system of the present application, the flue gas to be treated is heated before entering the desulfurization device, that is, the temperature of the flue gas to be treated entering the desulfurization device is increased, which is conducive to the removal of SO 3 , HCL, HF and other strong acid pollutants. At the same time, increasing the temperature can increase the amount of water sprayed at the rear end and promote the removal of SO 2Fully react with the absorbent to improve desulfurization efficiency and reduce the calcium-sulfur ratio;

[0026] (2) After passing through the SCR denitrification device, the high-temperature flue gas is formed. In addition to a part of the flue gas heat being exchanged with the flue gas to be treated entering the desulfurization device through the MGGH low-temperature section and the MGGH high-temperature section, the other part of the flue gas flows into the GGH from the clean flue gas inlet for heat exchange, that is, heat is exchanged with the flue gas entering the CO removal device. The heat released by the catalytic oxidation of CO is fully utilized;

[0027] (3) Adding MGGH after the denitrification device can reduce the flue gas temperature entering the GGH and avoid GGH jamming. The overall stability of the system is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the structure of the sintering flue gas multi-pollutant coordinated treatment system according to an embodiment of the present application.

[0029] Description of labels:

[0030] 11. MGGH low-temperature section; 12. MGGH high-temperature section; 2. Desulfurization device; 3. GGH; 4. Heating device; 5. CO removal device; 6. SCR denitrification device; 7. Dust removal device; 8. Bypass flue; 9. Control valve; 10. Draft device; 20. Chimney. DETAILED DESCRIPTION

[0031] Although the present invention can be easily embodied in different forms of embodiments, only some of the specific embodiments are shown in the drawings and will be described in detail in this specification. It should be understood that this description should be regarded as an exemplary illustration of the principles of the invention and is not intended to limit the invention to that described herein.

[0032] Thus, a feature indicated in this specification will be used to illustrate one of the features of an embodiment of the present invention, rather than implying that each embodiment of the present invention must have the described feature. In addition, it should be noted that this specification describes many features. Although some features can be combined together to illustrate possible system designs, these features can also be used in other combinations that are not explicitly described. Thus, unless otherwise stated, the described combinations are not intended to be limiting.

[0033] In the embodiments shown in the drawings, the indications of directions (such as up, down, left, right, front and back) used to explain the structure and movement of various elements of the present invention are not absolute but relative. These descriptions are appropriate when these elements are in the positions shown in the drawings. If the description of the positions of these elements changes, the indications of these directions also change accordingly.

[0034] The present application is further described in detail below with reference to the accompanying drawings and embodiments.

[0035] Meaning:

[0036] MGGH: It is the abbreviation of the intermediate heat medium flue gas heat exchanger system which uses heat medium water as the medium.

[0037] GGH: It is the abbreviation of Gas Gas Heater, which means flue gas heat exchanger.

[0038] SCR: It is the abbreviation of Selective Catalytic Reduction.

[0039] Example 1

[0040] According to an implementation shown in this embodiment, the structure can be seen in Figure 1 , wherein the same reference numerals denote corresponding components throughout the figures. It should be understood that the sintering flue gas multi-pollutant coordinated treatment system according to the present application can be used for the purification treatment of all steel sintering flue gases.

[0041] like Figure 1 As shown, the sintering flue gas multi-pollutant coordinated treatment system of this embodiment includes: MGGH, desulfurization device 2, dust removal device 7, GGH3, heating device 4, CO removal device 5, SCR denitrification device 6, bypass flue 8, regulating valve 9, induced draft device 10 and chimney 20.

[0042] In this embodiment, the CO removal device 5 is a CO catalytic oxidation reactor, the desulfurization device 6 is a circulating fluidized bed absorber, the GGH3 is a rotary GGH, the dust removal device 7 is a bag filter, and the induced draft device 10 is an induced draft fan. The catalyst in the CO removal device 5 is a precious metal catalyst. The heating device 4 is a direct-fired furnace with a built-in flue.

[0043] The MGGH includes an MGGH low temperature section 11 and an MGGH high temperature section 12. The MGGH low temperature section 11 is interlocked with the MGGH high temperature section 12. The MGGH high temperature section 12 uses high temperature flue gas to heat heat medium water and cools the flue gas at the same time; the MGGH low temperature section 11 uses the heated heat medium water to heat the flue gas to be treated and cools the heat medium water at the same time.

[0044] See also Figure 1, the MGGH low temperature section 11, the desulfurization device 2, the dust removal device 7, the CO removal device 5, the SCR denitrification device 6 and the MGGH high temperature section 12 are connected by pipelines in sequence along the flue gas flow direction. The raw flue gas inlet of GGH3 is connected to the gas outlet of the desulfurization device 2, the raw flue gas outlet of GGH3 is connected to the gas inlet of the CO removal device 5, the clean flue gas inlet of GGH3 is connected to the gas outlet of the MGGH high temperature section 12, the clean flue gas outlet of GGH3 is connected to the induced draft device 10 pipeline, and the induced draft device 10 is connected to the chimney 20 pipeline. The air inlet end of the built-in flue of the heating device 4 is connected to the raw flue gas inlet of GGH3, and the air outlet end of the built-in flue of the heating device 4 is connected to the air inlet of the CO removal device 5, so as to heat the flue gas to be treated entering the CO removal device 5.

[0045] One end of the bypass flue 8 is connected to the air inlet of the CO removal device 5, and the other end of the bypass flue 8 is connected to the air outlet of the CO removal device 5. A regulating valve 9 is provided on the bypass flue 8, the air inlet pipe of the CO removal device 5, and the air outlet pipe of the CO removal device 5.

[0046] Based on the above structural description, in this embodiment, see Figure 1 , the arrow direction in the figure is the flue gas flow direction. The flue gas from the sintering main exhaust port is heated by the MGGH low temperature section 11. The heat comes from the heat exchange of the MGGH high temperature section 12 at the outlet of the SCR denitrification device 6. The heated flue gas enters the desulfurization device 2 (circulating fluidized bed absorber) and the dust removal device 7 (bag dust collector). The flue gas after desulfurization and dust removal enters the GGH3 for heat exchange and temperature increase to reduce the denitrification heating end difference. Then, it enters the CO removal device 5 and the SCR denitrification device 6 after being heated by the heating device 4. The flue gas after CO removal and denitrification is successively removed and heat exchanged by the MGGH high temperature section 12 and GGH3, and then discharged to the chimney 20 through the induced draft device 10.

[0047] According to the general 260m 2 The sintering machine flue gas volume is 1000000Nm 3 / h, the original CO concentration of flue gas is 10000mg / Nm 3 It is estimated that the heat released by the complete catalytic oxidation of CO in the sintering flue gas will reach 26,500KW. If it is fully used to generate electricity, even if calculated at a power generation efficiency of 40%, the heat released by the catalytic oxidation of CO can generate 10,000 kWh of electricity per hour, and the potential for waste heat utilization is very large.

[0048] In this example, a CO removal device 5 is added to the desulfurization device 2 and the SCR denitration device 6. While removing CO, the heat released by CO is fully utilized. The CO concentration in the sintering flue gas is high. If the concentration is 10000 mg / Nm 3Considering 80% CO removal efficiency, the heat of CO catalytic oxidation can increase the flue gas temperature by about 60°C. The current heating temperature difference of conventional sintering SCR denitrification is only 30°C. After the oxidation reaction catalyzed by CO catalyst, the operating temperature can be increased from 280°C to above 320°C. The conventional medium and high temperature denitrification catalyst is selected to extend the service life of the denitrification catalyst.

[0049] At the same time, the temperature of the flue gas after denitration is still relatively high, and the potential for waste heat utilization is large. In addition to exchanging part of the heat with the flue gas at the air inlet of the SCR denitration device 6 through the CO removal device, in order to avoid the influence of the high-temperature flue gas of denitration on GGH3, the MGGH high-temperature section 12 is set at the outlet of the SCR denitration device 6, and the other part of the flue gas heat is exchanged with the flue gas at the air inlet of the desulfurization device 2 through heat transfer oil or other media. Compared with the conventional CO removal device, the temperature rise of catalytic oxidation is 30°C, and the CO removal efficiency is about 50-60%. This project can achieve more than 80% waste heat utilization by utilizing part of the waste heat to heat the flue gas at the desulfurization inlet, and the utilization efficiency is greatly improved.

[0050] In this embodiment, MGGH is used to increase the flue gas temperature entering the circulating fluidized bed desulfurization absorber, which is beneficial for removing SO 3 , HCL, HF and other strong acid pollutants. At the same time, increasing the temperature can increase the amount of water sprayed at the rear end and promote the removal of SO 2 Fully react with the absorbent to improve desulfurization efficiency and reduce the calcium-sulfur ratio. Relying on the circulating fluidized bed absorber and bag filter, it can stably achieve SO 2 、SO 3 , HCl, HF, heavy metal mercury and fine dust and other pollutants are removed, reducing the impact of flue gas pollutants on the precious metal catalyst in the CO removal device 5 and extending the service life of the catalyst.

[0051] The CO removal device 5 is arranged before the SCR denitration device 6 (along the flue gas flow direction). In the initial operation, the flue gas can be heated by the heating device 4 to meet the operating temperature requirement of the CO catalyst above 200°C. After stable operation, the flue gas can be heated only by the heat released after CO removal, and the temperature rise of the flue gas can be adjusted by the bypass flue 8 and the regulating valve 9. According to the actual operation situation, the heating device 4 is gradually withdrawn / closed. In this embodiment, because a direct-fired furnace with a built-in flue is used, the heating device 4 only needs to stop the gas supply when switching, and the start-stop switching is convenient.

[0052] For the temperature control of the whole system, the amount of flue gas passing through the CO removal device 5 can be adjusted mainly through the bypass flue 8 and the regulating valve 9, so as to control the CO removal amount and thus control the rise of flue gas temperature, so as to achieve the optimal economic operation of desulfurization and denitrification under the premise of satisfying the stable operation of the system.

[0053] The sintering flue gas multi-pollutant coordinated treatment system of this embodiment proposes a highly efficient coupled multi-pollutant coordinated CO removal system, which can be efficiently coupled with the CO removal process on the basis of the existing desulfurization and denitrification. At the same time, the heat released by the catalytic oxidation of CO is used to heat the desulfurization inlet flue gas temperature through MGGH, thereby increasing the desulfurization water spray volume, promoting the flue gas desulfurization reaction, and reducing the calcium-sulfur ratio, thereby achieving the lowest comprehensive operating cost, energy saving, consumption reduction, emission reduction and carbon reduction.

[0054] In addition, desulfurization is performed first and then CO removal to avoid the precious metal catalyst being damaged by SO 2 、SO 3 , HCl, HF, heavy metal mercury and fine dust and other sensitive substances. This embodiment adopts a circulating fluidized bed semi-dry desulfurization, connected with a CO removal device 5 using a precious metal catalyst and an SCR denitrification device 6. In addition, considering the coupling integration of the front and rear systems, a set of MGGH devices is set to transfer part of the heat of the high-temperature flue gas catalytically oxidized by CO to the desulfurization inlet for heating the flue gas at the desulfurization inlet. Relying on a circulating fluidized bed absorber with high turbulence, high density and two-stage high-efficiency reaction, the high-temperature section can remove strong acids (SO 3 , HCl, HF), and the low temperature section after water spraying removes SO 2 , can stably achieve SO 2 、SO 3 , HCl, HF, heavy metal mercury and fine dust and other pollutants are removed. While efficiently removing CO, the optimal economic operation of the multi-pollutant removal device is achieved, which not only reduces emissions but also reduces carbon emissions.

[0055] In this example, the sintering flue gas has multiple pollutants that are processed in a coordinated manner. After adding the CO removal device 5 on the basis of the desulfurization device 2 and the SCR denitrification device 6, in order to improve the stability and control ability of the system, an MGGH heat exchanger is set up to fully utilize the flue gas waste heat after CO oxidation to the flue gas before desulfurization; in order to further improve the control ability of flue gas waste heat utilization, a bypass adjustment function of the CO removal device is set up. After adding the CO removal device 5, the selection of the desulfurization water spray gun can be improved synchronously, so as to increase the water spray volume after the desulfurization flue gas temperature is increased; because the denitrification inlet flue gas temperature in this example can be increased to about 320°C after fully utilizing the CO waste heat, a medium-high temperature catalyst can be selected for denitrification, which is beneficial to improving the catalyst efficiency and extending the catalyst life.

[0056] The sintering flue gas multi-pollutant coordinated treatment system of this embodiment has the following advantages:

[0057] (1) Through the high-efficiency circulating fluidized bed absorber at the front end, multiple pollutants in the flue gas are synergistically removed, creating good flue gas conditions for the precious metal catalyst in the CO removal device 5, reducing the risk of catalyst poisoning and extending the service life of the catalyst.

[0058] (2) By installing MGGH and GGH3 at the outlet of the SCR denitrification device 6, a large amount of heat released during the catalytic oxidation removal of CO is fully utilized to achieve preheating recovery. The flue gas heat at the outlet of the SCR denitrification device 6 is exchanged to the desulfurization inlet, which increases the flue gas temperature at the desulfurization inlet, increases the desulfurization water spray volume, reduces the absorbent consumption, and reduces the operating cost of the desulfurization system; at the same time, the flue gas temperature entering the GGH heat exchanger is reduced, and the stability of the system operation is improved;

[0059] (3) Promote desulfurization and SO removal by increasing the temperature of the flue gas at the desulfurization inlet 3 , the ability to remove heavy metals and other pollutants, providing a cleaner environment for the CO catalyst and ensuring the removal efficiency and service life of the CO catalyst.

[0060] (4) By providing a bypass flue 8 and a regulating valve 9, the temperature of the flue gas entering the SCR denitrification device 6 and the GGH3 can be controlled.

[0061] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A sintering flue gas multi-pollutant coordinated treatment system, characterized in that: It includes MGGH, desulfurization device, GGH, heating device, CO removal device and SCR denitration device, the MGGH includes MGGH low temperature section and MGGH high temperature section, the MGGH low temperature section, desulfurization device, CO removal device, SCR denitration device and MGGH high temperature section are connected by pipelines in sequence along the flue gas flow direction; the heating device is used to heat the flue gas to be treated at the air inlet of the CO removal device; The raw flue gas inlet of the GGH is connected to the gas outlet of the desulfurization device, the raw flue gas outlet of the GGH is connected to the gas inlet of the CO removal device, and the clean flue gas inlet of the GGH is connected to the gas outlet of the high temperature section of the MGGH; The MGGH low temperature section is linked with the MGGH high temperature section. The MGGH high temperature section uses high temperature flue gas to heat heat medium water and cools the flue gas at the same time; the MGGH low temperature section uses the heated heat medium water to heat the flue gas to be treated and cools the heat medium water at the same time.

2. The sintering flue gas multi-pollutant coordinated treatment system according to claim 1 is characterized in that: It also includes a dust removal device, the air inlet of the dust removal device is connected to the air outlet of the desulfurization device, and the air outlet of the dust removal device is connected to the original flue gas inlet of the GGH.

3. The sintering flue gas multi-pollutant coordinated treatment system according to claim 1 is characterized in that: It also includes a bypass flue and a regulating valve. The two ends of the bypass flue are connected to the air inlet and the air outlet of the CO removal device respectively and one by one. The bypass flue, the air inlet pipe of the CO removal device and the air outlet pipe of the CO removal device are respectively provided with the regulating valve.

4. The sintering flue gas multi-pollutant coordinated treatment system according to claim 1 is characterized in that: The heating device is a direct-fired furnace with a built-in flue, and the built-in flue of the heating device is respectively connected to the original flue gas inlet of the GGH and the air inlet of the CO removal device.

5. The sintering flue gas multi-pollutant coordinated treatment system according to claim 1 is characterized in that: It also includes an air induction device and a chimney, wherein the clean smoke outlet of the GGH is connected to the air inlet of the air induction device, and the air outlet of the air induction device is connected to the chimney pipe.

6. The sintering flue gas multi-pollutant coordinated treatment system according to claim 1 is characterized in that: The desulfurization device is a circulating fluidized bed absorption tower, and the GGH is a rotary GGH.

7. The sintering flue gas multi-pollutant coordinated treatment system according to claim 1 is characterized in that: The catalyst in the CO removal device is a precious metal catalyst.

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