Cooperative treatment system for multiple pollutants in sintering flue gas

Abstract

The utility model 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] This application relates to industrial flue gas purification technology, and in particular to a multi-pollutant synergistic treatment system for sintering flue gas. Background Technology

[0002] The sintering process of steel production emits large volumes of flue gas and a variety of pollutants, including SO2 and NO. x Besides accounting for over 70% of the total emissions from the entire plant, it also contains large amounts of pollutants such as SO3, HCl, HF, heavy metals, and dioxins. Furthermore, carbon monoxide emissions account for approximately 70% of the total emissions from the entire steel plant. The sintering flue gas contains approximately 1-2% CO (approximately 8000-20000 mg / m³). 3 CO has become one of the pollutants in sintering flue gas that urgently needs to be treated. According to relevant data, approximately one-quarter of the carbon (C) produced during the sintering process is ultimately emitted as incomplete combustion, resulting in about 15-20% of energy being emitted in the form of CO in the sintering flue gas, causing a huge waste of energy. Currently, CO emission reduction in sintering flue gas in the steel industry is mainly achieved through flue gas recirculation, 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 the sintered ore.

[0003] With the introduction of CO emission standards in various regions, relying solely on front-end CO treatment is no longer sufficient to meet emission requirements, necessitating the addition of back-end CO treatment processes. For back-end CO treatment, catalytic oxidation is generally used to oxidize CO into CO2, with precious metal catalysts currently being the most effective. However, precious metal catalysts are easily deactivated by other pollutants in flue gas such as SO2, SO3, and NH3, resulting in short catalyst lifespans and unstable CO removal systems. Therefore, CO removal processes cannot simply consider catalyst activity; they also need to address the synergistic removal of other pollutants, particularly the removal of acidic gases such as SO2, SO3, and HCl from the flue gas upstream of the CO catalyst.

[0004] Currently, CO treatment at the downstream end of sintering flue gas needs to be combined with existing desulfurization and denitrification technologies. Flue gas desulfurization devices spray water into the absorption tower to wet the surface of particles, creating favorable ion reaction conditions for flue gas desulfurization. The larger the spray volume, the more thorough the desulfurization reaction, and the lower the absorbent consumption. To avoid agglomeration inside the absorption tower, the flue gas temperature inside the desulfurization unit is generally not lower than 80℃. Therefore, limited by the flue gas temperature at the desulfurization inlet, the amount of water sprayed is relatively small, resulting in a high calcium-to-sulfur ratio in the desulfurization process.

[0005] The prior art discloses a sintering flue gas CO removal system and method, including a semi-dry desulfurization reactor, a GGH heat exchanger, a hot blast stove, an SCR reactor, and a noble metal catalytic oxidation reactor. After the sintering flue gas passes through the semi-dry desulfurization device, the 80-90℃ flue gas is first heated by the GGH heat exchanger, and then, under the action of the noble metal CO catalyst, the CO is removed, and the flue gas is heated by the heat released by the CO reaction. The heated flue gas generates steam through the heat exchanger, is combined into a steam pipe network, and then enters the SCR reactor for denitration. The catalytic reactor is arranged before the heating furnace, and the catalytic temperature of the catalyst needs to be at least 200℃ or above. Although the system can be heated by the hot blast stove, the GGH heat exchange process is slow, and it takes a long time to raise the temperature to the required temperature for the CO reaction. Although the noble metal CO catalyst has high activity, it is easily affected by SO2, dust and other pollutants in the flue gas, and is easily deactivated, and the system stability needs to be improved.

[0006] The prior art discloses a sintering flue gas CO removal NO x The method includes a dust and desulfurization system, a high-temperature hot blast stove, a GGH heat exchanger, a denitration tower, etc. The high-temperature flue gas at the sintering outlet is used to exchange heat with the flue gas at the desulfurization outlet, and then enters the desulfurization tower for desulfurization. Then, the flue gas is mixed with the high-temperature air at the outlet of the hot blast stove, and then enters the denitration tower, and the removal of NO x and CO is completed in the denitration tower. After heat exchange, the flue gas is discharged into a chimney. This technology still needs the hot blast stove to provide high-temperature flue gas to mix with the desulfurized flue gas, and does not fully utilize the heat released by the CO catalytic oxidation, and the operation cost is high. Practical new type content

[0007] To solve at least one of the problems of not fully utilizing the heat released by the CO catalytic oxidation, high operation cost, and poor system stability, the present application provides a sintering flue gas multi-pollutant collaborative treatment system.

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

[0009] The application discloses a sintering flue gas multi-pollutant collaborative treatment system which comprises an MGGH, a desulfurization device, a GGH, a heating device, a CO removal device and an SCR denitration device, wherein 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 in a flue gas flow direction through pipelines, respectively, the heating device is used for heating the to-be-treated flue gas at an air inlet of the CO removal device, a raw flue gas inlet of the GGH is communicated with an air outlet of the desulfurization device, a raw flue gas outlet of the GGH is communicated with the air inlet of the CO removal device, a clean flue gas inlet of the GGH is communicated with an air outlet of the MGGH high-temperature section, the MGGH low-temperature section and the MGGH high-temperature section are connected in a chain, the MGGH high-temperature section is used for heating heat medium water by using high-temperature flue gas and simultaneously cooling the flue gas, and the MGGH low-temperature section is used for heating the to-be-treated flue gas by using the heated heat medium water and simultaneously cooling the heat medium water.

[0010] By adopting the technical scheme, after the to-be-treated flue gas enters the sintering flue gas multi-pollutant collaborative treatment system, the to-be-treated flue gas sequentially flows through the MGGH low-temperature section, the desulfurization device, is heated in the MGGH low-temperature section (the heat is derived from heat exchange of the MGGH high-temperature section at the outlet of the denitration device), sequentially enters the CO removal device through the raw flue gas inlet of the GGH and the raw flue gas outlet of the GGH, the flue gas is heated by the GGH, the temperature difference of the heating end of the denitration device is reduced, then flows through the CO removal device, the temperature of the flue gas is increased due to heat released by the CO catalytic oxidation reaction, and then flows out through the SCR denitration device to form high-temperature flue gas, the high-temperature flue gas passes through the MGGH high-temperature section, the MGGH low-temperature section and the MGGH high-temperature section are connected in a chain, the MGGH high-temperature section is used for heating heat medium water by using high-temperature flue gas and simultaneously cooling the flue gas, and the MGGH low-temperature section which is arranged before the air inlet of the desulfurization device is used for heating the to-be-treated flue gas by using the heated heat medium water and simultaneously cooling the heat medium water. The to-be-treated flue gas is heated and then enters the desulfurization device, the temperature of the to-be-treated flue gas entering the desulfurization device is increased, which is beneficial to removal of strong acidic pollutants such as SO3, HCL and HF, meanwhile, increasing the temperature can increase the water spraying amount at the rear end, promote the reaction of SO2 in the flue gas and the absorbent, improve the desulfurization efficiency, reduce the calcium-sulfur ratio, reduce the absorbent consumption and reduce the operation cost.

[0011] Meanwhile, the outlet of the high-temperature section of the MGGH is communicated with the inlet of the GGH for the clean flue gas, so that the high-temperature flue gas formed after passing through the SCR denitration device is exchanged with the flue gas entering the desulfurization device through the low-temperature section of the MGGH and the high-temperature section of the MGGH, and another part of the flue gas flows into the GGH from the inlet of the GGH for the clean flue gas to be exchanged with the flue gas entering the CO removal device. The heat released by the catalytic oxidation of CO can be fully utilized. By adding the MGGH after the denitration device, the temperature of the flue gas entering the GGH is reduced, and the clogging of the GGH is avoided. The overall stability of the system is good.

[0012] Preferably, the system further comprises a dust removal device, an inlet of the dust removal device being communicated with an outlet of the desulfurization device, and an outlet of the dust removal device being communicated with the inlet of the GGH for the raw flue gas.

[0013] By adopting the above technical scheme, as a specific structural example, the dust removal device can purify the dust in the flue gas after desulfurization, thereby avoiding the catalyst inactivation caused by the dust entering the CO removal device, and ensuring the stable operation of the entire system.

[0014] Preferably, the system further comprises a bypass flue and a regulating valve, two ends of the bypass flue being respectively and one-to-one communicated with the inlet of the CO removal device and the outlet of the CO removal device, and the bypass flue, the inlet pipeline of the CO removal device and the outlet pipeline of the CO removal device being respectively provided with the regulating valve.

[0015] By adopting the above technical scheme, as a specific structural example, the bypass flue and the regulating valve are designed, and the temperature of the flue gas entering the SCR denitration device and the GGH heat exchanger can be controlled through the regulating valves on the bypass flue, the inlet pipeline of the CO removal device and the outlet pipeline of the CO removal device, so that the system can still operate at the designed temperature when the CO concentration of the sintering flue gas changes.

[0016] Preferably, the heating device is a direct-fired furnace with an internal flue, and the internal flue of the heating device is respectively communicated with the inlet of the GGH for the raw flue gas and the inlet of the CO removal device.

[0017] By adopting the above technical scheme, as a structural example, the heating device is provided to control the influence of the change of the CO concentration in the flue gas on the temperature of the flue gas of the system.

[0018] The CO removal device is arranged at the gas inlet of the SCR denitration device, in the initial operation stage, the flue gas can be heated by the heating device to meet the operating temperature requirement of the CO catalyst of 200 DEG C or above, after stable operation, the flue gas can be heated only by the heat released by the catalytic oxidation in the CO removal device, and the temperature increase of the flue gas is adjusted by the adjusting valve on the bypass flue of the CO removal device, and the heating device is gradually withdrawn and no longer used.

[0019] Preferably, the induced draft device and the chimney are further included, the net flue gas outlet of the GGH is communicated with the gas inlet of the induced draft device, and the gas outlet of the induced draft device is connected with the chimney pipeline.

[0020] By adopting the technical scheme, as a structural example, the flue gas after heat exchange of 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 meeting the functional parameter requirement.

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

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

[0023] By adopting the technical scheme, as a structural example, the circulating fluidized bed semi-dry desulfurization is adopted, the CO removal device adopting the noble metal catalyst and the SCR denitration device are connected, the coupling integration of the front and rear systems is considered, and a set of MGGH device is arranged to exchange heat of part of the heat of the high-temperature flue gas of the CO catalytic oxidation to the desulfurization inlet, for heating the flue gas at the inlet of the desulfurization device, and the circulating fluidized bed absorption tower with high turbulence, high density and double-stage high-efficiency reaction is relied on, the strong acid (SO3, HCl and HF) can be removed in the high-temperature section, and SO2 can be removed after water spraying in the low-temperature section, so that the pollutants such as SO2, SO3, HCl, HF, heavy metal mercury and fine dust can be stably removed, the CO can be efficiently removed, and the optimal economic operation of the multi-pollutant removal device is realized, that is, the emission reduction and the carbon reduction are realized.

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

[0025] (1) The sintering flue gas multi-pollutant collaborative treatment system of the present application, after the flue gas is heated and enters the desulfurization device, the temperature of the flue gas entering the desulfurization device is improved, which is beneficial to the removal of strong acid pollutants such as SO3, HCL and HF, at the same time, the temperature increase can increase the water spraying amount of the rear end, promote the reaction of SO2 in the flue gas and the absorbent, improve the desulfurization efficiency, and reduce the calcium-sulfur ratio.

[0026] (2) the high-temperature flue gas formed after passing through the SCR denitration device, except for a part of the flue gas heat exchanged to the flue gas to be treated entering the desulfurization device through the low-temperature section and the high-temperature section of the MGGH, another part of the flue gas flows into the GGH from the net flue gas inlet of the GGH for heat exchange, that is, heat exchanged to the flue gas entering the CO removal device. Make full use of the heat released by the CO catalytic oxidation;

[0027] (3) By adding MGGH after the denitration device, the temperature of the flue gas entering the GGH is reduced to avoid the clogging of the GGH. The overall stability of the system is good. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a structural schematic diagram of a sintering flue gas multi-pollutant co-processing system of the embodiment of the present application.

[0029] Label explanation:

[0030] 11, low-temperature section of MGGH; 12, high-temperature section of MGGH; 2, desulfurization device; 3, GGH; 4, heating device; 5, CO removal device; 6, SCR denitration device; 7, dust removal device; 8, bypass flue; 9, regulating valve; 10, induced draft device; 20, chimney. DETAILED DESCRIPTION

[0031] Although the present application can be easily embodied in different forms of embodiments, only some specific embodiments thereof are shown in the drawings and described in detail in the present specification, and it can be understood that the present specification should be considered as a demonstrative explanation of the principles of the present application, and is not intended to limit the present application to what is described herein.

[0032] Therefore, one feature indicated in the present specification will be used to explain one feature of one embodiment of the present application, and it is not implied that each embodiment of the present application must have the explained feature. In addition, it should be noted that the present specification describes many features. Although certain features can be combined together to show possible system designs, these features can also be used in other combinations not explicitly described. Therefore, 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) are used to explain the structure and movement of various elements of the present application, which are not absolute but relative. When these elements are in the position shown in the drawings, these indications are appropriate. If the position of these elements changes, the indications of directions also change accordingly.

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

[0035] Word meaning explanation:

[0036] MGGH: is the abbreviation of Medium Gas Gas Heater system, which is a medium-temperature medium gas-gas heater system.

[0037] GGH: is the abbreviation of Gas Gas Heater, which is a gas-gas heater.

[0038] SCR: is the abbreviation of Selective Catalytic Reduction, which is a selective catalytic reduction.

[0039] Example 1

[0040] A sintering flue gas multi-pollutant co-processing system according to one embodiment shown in the present embodiment can be seen from Figure 1 , wherein the same reference signs represent corresponding parts throughout the view. It should be understood that the sintering flue gas multi-pollutant co-processing system according to the present application can be used for the purification treatment of all steel sintering flue gas.

[0041] As shown in Figure 1 , the sintering flue gas multi-pollutant co-processing system of the present embodiment comprises: an MGGH, a desulfurization device 2, a dust removal device 7, a GGH 3, a heating device 4, a CO removal device 5, an SCR denitration device 6, a bypass flue 8, a regulating valve 9, an induced draft device 10, and a chimney 20.

[0042] In the present embodiment, the CO removal device 5 is a CO catalytic oxidation reactor, the desulfurization device 6 is a circulating fluidized bed absorption tower, the GGH 3 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 noble metal catalyst. The heating device 4 is a direct-fired furnace with an internal flue.

[0043] The MGGH comprises an MGGH low-temperature section 11 and an MGGH high-temperature section 12, the MGGH low-temperature section 11 is connected to the MGGH high-temperature section 12, the MGGH high-temperature section 12 uses high-temperature flue gas to heat the heat medium water and simultaneously cools the flue gas; the MGGH low-temperature section 11 uses the heated heat medium water to heat the flue gas to be treated and simultaneously cools the heat medium water.

[0044] Referring to Figure 1, MGGH low temperature section 11, desulfurization device 2, dust removal device 7, CO removal device 5, SCR denitration device 6 and MGGH high temperature section 12 are sequentially connected in the flue gas flow direction. The original flue gas inlet of GGH 3 is communicated with the gas outlet of desulfurization device 2, the original flue gas outlet of GGH 3 is communicated with the gas inlet of CO removal device 5, the clean flue gas inlet of GGH 3 is communicated with the gas outlet of MGGH high temperature section 12, and the clean flue gas outlet of GGH 3 is connected with induced draft device 10, and the induced draft device 10 is connected with chimney 20. The gas inlet end of the built-in flue of heating device 4 is communicated with the original flue gas inlet of GGH 3, and the gas outlet end of the built-in flue of heating device 4 is communicated with the gas inlet of CO removal device 5, which is used for heating the flue gas to be treated entering the CO removal device 5.

[0045] One end of bypass flue 8 is communicated with the gas inlet of CO removal device 5, and the other end of bypass flue 8 is communicated with the gas outlet of CO removal device 5. An adjusting valve 9 is arranged on the bypass flue 8, the gas inlet pipeline of CO removal device 5 and the gas outlet pipeline of CO removal device 5.

[0046] Based on the above structural description, in the embodiment, referring to Figure 1 , the arrow direction in the figure is the flue gas flow direction. The flue gas of the sintering main exhaust port is heated by MGGH low temperature section 11, and the heat source is the heat exchange of MGGH high temperature section 12 at the outlet of SCR denitration device 6. The heated flue gas enters desulfurization device 2 (circulating fluidized bed absorption tower) and dust removal device 7 (bag filter), and after desulfurization and dust removal treatment, the flue gas enters GGH 3 for heat exchange and temperature rise, reduces the temperature difference of the denitration heating end, and then enters CO removal device 5 and SCR denitration device 6 after heating by heating device 4. The flue gas after CO removal and denitration is heat exchanged by MGGH high temperature section 12 and GGH 3, and then discharged to chimney 20 by induced draft device 10.

[0047] According to general 260m 2 The sintering flue gas volume is 1000000Nm 3 / h, and the original CO concentration of flue gas is 10000mg / Nm 3 The heat released by complete catalytic oxidation of CO in sintering flue gas will reach 26500KW, and if it is used for power generation, even if the power generation efficiency is 40%, the heat released by CO catalysis can generate 10000 degrees of electricity per hour, and the waste heat utilization potential is very large.

[0048] In this example, CO removal device 5 is added on the basis of desulfurization device 2 and SCR denitration device 6, and the heat released by CO is fully utilized while removing CO. The CO concentration in sintering flue gas is high, and if it is 10000mg / Nm 3The heat of the catalytic oxidation of CO can increase the temperature of the flue gas by about 60°C, considering 80% CO removal efficiency. According to the current conventional sintering SCR denitration heating temperature difference of only 30°C, after the oxidation reaction catalyzed by the CO catalyst, the operating temperature can be increased from 280°C to more than 320°C, and the conventional medium-high temperature denitration catalyst is selected to prolong the service life of the denitration catalyst.

[0049] The temperature of the flue gas after simultaneous denitrification is still relatively high, and the waste heat utilization potential is large. A part of the heat is exchanged by the CO removal device to the flue gas at the inlet of the SCR denitration device 6. In order to avoid the influence of the high-temperature flue gas after denitrification on the GGH 3, the MGGH high-temperature section 12 is arranged at the outlet of the SCR denitration device 6, and the other part of the flue gas heat is exchanged by heat conduction oil or other medium to the flue gas at the inlet of the desulfurization device 2. 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%. In this project, more than 80% of the waste heat can be utilized by using part of the waste heat for heating the flue gas at the inlet of the desulfurization device, and the utilization efficiency is greatly improved.

[0050] The embodiment improves the temperature of the flue gas entering the circulating fluidized bed desulfurization absorption tower by MGGH, which is beneficial to the removal of strong acid pollutants such as SO3, HCL and HF in the high-temperature section of the flue gas. At the same time, increasing the temperature can increase the water injection amount at the rear end, promote the reaction of SO2 in the flue gas and the absorbent, improve the desulfurization efficiency, and reduce the calcium-sulfur ratio. Relying on the circulating fluidized bed absorption tower and the bag-type dust collector, SO2, SO3, HCl, HF, heavy metal mercury and fine dust pollutants can be stably removed, the influence of flue gas pollutants on the noble metal catalyst in the CO removal device 5 is reduced, and the service life of the catalyst is prolonged.

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

[0052] For the temperature control of the overall system, the flue gas amount passing through the CO removal device 5 can be adjusted by the bypass flue 8 and the regulating valve 9, the CO removal amount is controlled, and the flue gas temperature rise is controlled. Under the premise of meeting the stable operation of the system, the optimal economic operation of desulfurization and denitrification is realized.

[0053] The sintering flue gas multi-pollutant collaborative treatment system of the embodiment proposes a high-efficiency coupled multi-pollutant collaborative CO removal system, which can be efficiently coupled with the CO removal process on the basis of the existing desulfurization and denitrification, and can heat the desulfurization inlet flue gas temperature through the MGGH by using the heat released by the CO catalytic oxidation, increase the desulfurization water injection amount, promote the flue gas desulfurization reaction, reduce the calcium-sulfur ratio, realize the lowest comprehensive operation cost, save energy and reduce consumption, and reduce carbon emissions.

[0054] In addition, the CO removal is performed after the desulfurization, which avoids the failure of the noble metal catalyst due to the sensitive substances such as SO2, SO3, HCl, HF, heavy metal mercury and fine dust in the flue gas. The embodiment adopts the circulating fluidized bed semi-dry desulfurization, connects the CO removal device 5 using the noble metal catalyst and the SCR denitrification device 6, and sets a set of MGGH device to exchange part of the heat of the high-temperature flue gas after the CO catalytic oxidation to the desulfurization inlet for heating the flue gas at the desulfurization inlet. The circulating fluidized bed absorption tower has high turbulence, high density and double-stage efficient reaction. The strong acid (SO3, HCl, HF) can be removed in the high-temperature section, and SO2 can be removed in the low-temperature section after water injection, which can stably realize the removal of pollutants such as SO2, SO3, HCl, HF, heavy metal mercury and fine dust, efficiently remove CO, and realize the optimal economic operation of the multi-pollutant removal device, which reduces emissions and reduces carbon.

[0055] The sintering flue gas multi-pollutant collaborative treatment of the embodiment increases the CO removal device 5 on the basis of the desulfurization device 2 and the SCR denitrification device 6, sets the MGGH heat exchanger to fully utilize the flue gas waste heat after the CO oxidation to the flue gas before the desulfurization, sets the bypass adjustment function of the CO removal device to further improve the control ability of the flue gas waste heat utilization, and increases the CO removal device 5 to simultaneously improve the selection of the desulfurization water injection lance to increase the water injection amount after the desulfurization flue gas temperature is increased. The denitrification inlet flue gas temperature in the embodiment can be increased to about 320℃ after the CO waste heat is fully utilized, the medium-high temperature catalyst can be selected for the denitrification, and the catalyst efficiency and the catalyst service life are improved.

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

[0057] (1) The multi-pollutants in the flue gas are collaboratively removed by the front-end high-efficiency circulating fluidized bed absorption tower, which creates good flue gas conditions for the noble metal catalyst in the CO removal device 5, reduces the catalyst poisoning risk, and prolongs the catalyst service life.

[0058] (2) By setting MGGH and GGH3 at the outlet of the SCR denitration device 6, the heat released in the process of catalytic oxidation removal of CO is fully utilized to realize preheating recovery. The heat of flue gas at the outlet of the SCR denitration device 6 is exchanged to the desulfurization inlet, the flue gas temperature at the desulfurization inlet is improved, the water spraying amount of desulfurization is improved, the absorbent consumption is reduced, and the operation cost of the desulfurization system is reduced; at the same time, the flue gas temperature entering the GGH heat exchanger is reduced, and the stability of system operation is improved;

[0059] (3) By increasing the flue gas temperature at the desulfurization inlet, the ability of desulfurization, SO3 removal, heavy metal and other pollutant removal is promoted, a cleaner environment is provided for the CO catalyst, and the removal efficiency and service life of the CO catalyst are ensured.

[0060] (4) By setting the bypass flue 8 and the adjusting valve 9, the temperature of flue gas entering the SCR denitration device 6 and the GGH3 can be controlled.

[0061] The specific embodiments are only an explanation of the present application, and are not a limitation of the present application, and those skilled in the art can make modifications to the embodiments without creative contribution according to the needs after reading the present specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A sintering off-gas multi-pollutant co-processing system, characterized by, The system comprises a MGGH, a desulfurization device, a GGH, a heating device, a CO removal device and an SCR denitration device, the MGGH comprises a MGGH low-temperature section and a 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 in the flue gas flow direction respectively; the heating device is used for heating the flue gas to be treated at the gas inlet of the CO removal device. The original flue gas inlet of the GGH is communicated with the gas outlet of the desulfurization device, the original flue gas outlet of the GGH is communicated with the gas inlet of the CO removal device, and the clean flue gas inlet of the GGH is communicated with the gas outlet of the MGGH high-temperature section. The MGGH low-temperature section and the MGGH high-temperature section are connected in series, the MGGH high-temperature section is used for heating heat medium water and cooling flue gas at the same time, and the MGGH low-temperature section is used for heating flue gas to be treated and cooling heat medium water at the same time.

2. The sintering off-gas multi-pollutant co-processing system according to claim 1, characterized in that, The system further comprises a dust removal device, the gas inlet of the dust removal device is communicated with the gas outlet of the desulfurization device, and the gas outlet of the dust removal device is communicated with the original flue gas inlet of the GGH.

3. The sintering off-gas multi-pollutant co-processing system according to claim 1, characterized in that, The system further comprises a bypass flue and a regulating valve, the two ends of the bypass flue are respectively communicated with the gas inlet of the CO removal device and the gas outlet of the CO removal device one by one, and the bypass flue, the gas inlet pipeline of the CO removal device and the gas outlet pipeline of the CO removal device are respectively provided with the regulating valve.

4. The sintering off-gas multi-pollutant co-processing system according to claim 1, characterized in that, The heating device is a direct-fired furnace with an internal flue, and the internal flue of the heating device is communicated with the original flue gas inlet of the GGH and the gas inlet of the CO removal device respectively.

5. The sintering off-gas multi-pollutant co-processing system according to claim 1, wherein, The system further comprises an induced draft device and a chimney, the clean flue gas outlet of the GGH is communicated with the gas inlet of the induced draft device, and the gas outlet of the induced draft device is connected with the chimney in a pipeline mode.

6. The sinter plant off-gas multi-pollutant co-operative treatment system according to claim 1, characterized in that, The desulfurization device is a circulating fluidized bed absorption tower, and the GGH is a rotary GGH.

7. The sintering off-gas multi-pollutant co-operative treatment system according to claim 1, characterized in that, The catalyst in the CO removal device is a noble metal catalyst.

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