System for eliminating CO in sintering flue gas

Abstract

The utility model discloses a system for eliminating CO in sintering flue gas. Comprising a hot blast stove used for burning blast furnace gas and combustion-supporting gas to obtain first flue gas; the heat exchanger is used for allowing the second flue gas to release heat and heating the first sintering flue gas for the first time; the first sintering flue gas is sintering flue gas from which CO is to be removed; the second flue gas after heat release of the heat exchanger is flue gas to be discharged; the mixing chamber is used for mixing the first flue gas with the first sintering flue gas which is heated for the first time, so that the first sintering flue gas is heated for the second time, and then the second flue gas is obtained; the power device is used for providing power for flue gas flowing; and the flue network is used for connecting the hot blast stove, the heat exchanger, the mixing chamber and the power device so as to allow flue gas to enter, be discharged and circulate.

Description

Technical Field

[0001] The utility model relates to the technical field of iron and steel smelting, and particularly relates to a system for removing CO in sintering flue gas. Background Art

[0002] In the technical field of iron and steel smelting, since the sintering process is responsible for the treatment of various types of solid wastes in the steel plant, the sintering process is the process with the largest pollutant emissions and the most types of pollutants in the long-process iron and steel process. The CO concentration in sintering flue gas is as high as 6000 - 9000mg / Nm 3 , and the total amount of CO emitted by all sintering machines in the country every year is as high as 2 billion standard cubic meters, which is equivalent to 8 - 10 billion standard cubic meters of blast furnace gas discharged, resulting in huge energy waste and environmental pollution. At present, the problem of CO pollution in sintering flue gas has become a bottleneck problem restricting the greening of iron and steel production, and it has also become one of the most difficult environmental protection problems for local environmental protection departments to solve.

[0003] The existing technologies for treating CO in sintering flue gas are basically concentrated in CO catalytic oxidation. Many catalyst products have been put into actual production lines for experiments. However, due to the complex types of pollutants in sintering flue gas, the catalyst is extremely prone to poisoning. The experimental results show that the service life of noble metal catalysts is basically no more than half a year, and the service life of non-noble metal catalysts with lower prices is generally only about three months. Frequent replacement of catalysts has led to a substantial increase in the production cost of sintering, which is difficult for enterprises to bear. Therefore, the development of a low-cost sintering flue gas CO emission reduction technology has become a need for the country and enterprises. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a system for removing CO in sintering flue gas, which can remove CO in sintering flue gas with less or no use of catalysts, thereby reducing the cost of removing CO in sintering flue gas.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A system for removing CO in sintering flue gas, comprising:

[0007] A hot blast stove, which is used to burn blast furnace gas and combustion-supporting gas to obtain a first flue gas;

[0008] A heat exchanger, which is used for the second flue gas to release heat and heat the first sintering flue gas for the first time; the first sintering flue gas is the sintering flue gas from which CO is to be removed; the second flue gas after releasing heat in the heat exchanger is the flue gas to be discharged;

[0009] A mixing chamber, which is used to mix the first flue gas with the first sintering flue gas after the first heating to heat the first sintering flue gas for the second time to obtain the second flue gas;

[0010] A power device for providing power for the flue gas flow;

[0011] A flue gas network for connecting the hot blast stove, the heat exchanger, the mixing chamber and the power device to allow the flue gas to enter, discharge and circulate.

[0012] Optionally, the combustion-supporting gas is a part of the first sintering flue gas, and the flue gas network includes a first flue with a first end connected to the hot blast stove, and the first flue is used to introduce a part of the first sintering flue gas;

[0013] Alternatively, the combustion-supporting gas is a part of the second flue gas that has not flowed through the heat exchanger, and the flue gas network includes a second flue with a first end connected to the hot blast stove, and the second flue is used to introduce a part of the second flue gas that has not flowed through the heat exchanger;

[0014] Alternatively, the combustion-supporting gas is a part of the second flue gas after heat release in the heat exchanger, and the flue gas network includes a third flue with a first end connected to the hot blast stove, and the third flue is used to introduce a part of the second flue gas after heat release in the heat exchanger;

[0015] Alternatively, the combustion-supporting gas is air, and the flue gas network includes a fourth flue with a first end connected to the hot blast stove, and the fourth flue is used to introduce external air.

[0016] Optionally, it further includes a starting heat source, and the starting heat source is used to burn natural gas and the combustion-supporting gas to generate a third flue gas during the starting stage;

[0017] The mixing chamber is used to mix the first flue gas, the third flue gas and the first sintering flue gas after the first heating during the starting stage to perform the second heating on the first sintering flue gas, and then obtain the second flue gas.

[0018] Optionally, the flue gas network includes a main intake flue and a main exhaust flue, and the power device includes a main control fan, and the main control fan is arranged at the main intake flue or the main exhaust flue.

[0019] Optionally, it further includes a gas preheater for preheating the blast furnace gas, and the gas preheater is respectively connected to the heat exchanger and the hot blast stove, and the gas preheater is used to exchange heat between the second flue gas after heat release in the heat exchanger and the blast furnace gas.

[0020] Optionally, the combustion-supporting gas is a part of the second flue gas after heat release in the heat exchanger. The flue gas network includes a third flue. The first end of the third flue is connected to the hot blast stove, and the second end of the third flue is connected to the main exhaust flue position. The power device includes a main control fan and a combustion-supporting fan. The main control fan is arranged on the main exhaust flue, and the combustion-supporting fan is arranged on the third flue.

[0021] Alternatively, a gas desulfurization device is further arranged between the gas preheater and the hot blast stove.

[0022] Optionally, the heat exchanger includes one or more of a switching regenerative heat exchanger, a rotary regenerative heat exchanger, a plate heat exchanger, a tubular heat exchanger, and a heat pipe heat exchanger.

[0023] In the technical solution of the present utility model, by arranging a hot blast stove, blast furnace gas and combustion-supporting gas are burned to generate high-temperature first flue gas. The sintering flue gas to be treated (the first sintering flue gas) is first heated by arranging a self-coupled heat exchanger. Then the first flue gas is mixed with the first sintering flue gas after the first heating. During the mixing process with the high-temperature first flue gas, the first sintering flue gas is secondarily heated. During the two heating processes, CO fully reacts with oxygen and is thus eliminated. At this time, the mixed gas (the second flue gas) of the first sintering flue gas and the first flue gas still has a relatively high temperature. The second flue gas is introduced into the self-coupled heat exchanger for heat release, and the released heat is used for the first heating of the first sintering flue gas. Thereby, it replaces the method of catalytic oxidation of CO with a catalyst in the prior art to eliminate CO in the sintering flue gas. At the same time, the heat of the second flue gas is fully utilized, saving energy consumption. Thus, it is possible to completely not use a catalyst, or only use a relatively small amount of catalyst to complete the elimination of CO. Compared with the prior art that requires frequent catalyst replacement, it can not only reduce costs but also reduce problems such as shutdown caused by catalyst replacement. Description of the Drawings

[0024] Figure 1 It is a schematic diagram of the first system for eliminating CO in the sintering flue gas;

[0025] Figure 2 It is a schematic diagram of the second system for eliminating CO in the sintering flue gas;

[0026] Figure 3 It is a schematic diagram of the third system for eliminating CO in the sintering flue gas.

[0027] In the figure, 1. Heat exchanger; 2. Hot blast stove; 3. Mixing chamber; 4. Main control fan; 5. Gas preheater; 6. Gas desulfurization device; 7. Combustion-supporting fan; 8. Starting heat source; 9. Purification system; 11. Regenerator; 12. Reversing valve; 101. Sintering machine; 102. Desulfurization system; 103. Dust removal system; 104. Denitration system; 105. Main exhaust fan; 106. Smoke exhaust chimney; 111. Main intake flue; 112. Main exhaust flue; 113. Third flue. Specific embodiments

[0028] Here, the exemplary embodiments will be described in detail, and the examples are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. On the contrary, they are merely examples of devices or methods consistent with some aspects of the present invention. The term "plurality" herein refers to two or more.

[0029] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other implementation manners obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope protected by the present invention.

[0030] Hereinafter, the embodiments will be described with reference to the drawings. In addition, the embodiments shown below do not impose any limitation on the content of the utility model described in the claims. Additionally, all the content of the configurations shown in the following embodiments is not necessarily essential for the solution of the utility model described in the claims.

[0031] See Figures 1-3, the present utility model provides a system for removing CO in sintering flue gas, including: a hot blast stove 2, which is used to burn blast furnace gas and combustion-supporting gas to obtain a first flue gas. The blast furnace gas is preferably various gases, etc., and further preferably blast furnace gas. A heat exchanger 1, which is used for the second flue gas to release heat and heat the first sintering flue gas for the first time. Here, the second flue gas refers to the second flue gas generated in the previous time period, and the heat released by the second flue gas is used to heat the first sintering flue gas for the first time; the first sintering flue gas is the sintering flue gas from which CO is to be removed; the second flue gas after releasing heat in the heat exchanger 1 is the flue gas to be discharged; a mixing chamber 3, which is used to mix the first flue gas (at a higher temperature) with the first sintering flue gas after the first heating to heat the first sintering flue gas for the second time, thereby obtaining the second flue gas. During the process of the first sintering flue gas being heated for the first time, CO in the first sintering flue gas reacts with oxygen and is partially or completely removed. If not all of the CO in the first sintering flue gas is removed during the first heating, the remaining CO will fully react with oxygen during the second heating and be removed. The second flue gas is the mixture of the first flue gas and the first sintering flue gas after the first heating. It should be noted here that the place where the first flue gas and the first sintering flue gas converge is the mixing chamber 3. The mixing chamber 3 can refer to a structure specifically set for mixing the first flue gas and the first sintering flue gas; it can also not specifically set a structure as the mixing chamber 3. The flue for flowing the first flue gas and the flue for flowing the first sintering flue gas converge in a flue, and the mixture is carried out in this flue, then the mixing place of this flue is the mixing chamber 3. For example, the first flue gas flows out from the outlet flue of the hot blast stove 2, and the first sintering flue gas flows out from the first outlet flue of the heat exchanger 1. After the two outlet flues converge, they are connected to the second inlet flue of the heat exchanger 1, and the place where the two outlet flues converge is the mixing chamber 3. Subsequently, the second flue gas enters the heat exchanger 1 to release heat to heat the first sintering flue gas newly entering the heat exchanger 1 for the first time. A power device for providing power for the flow of flue gas, which is used to provide power for the flow of flue gas in this system. A flue gas network for connecting the hot blast stove 2, the heat exchanger 1, the mixing chamber 3 and the power device for the entry, discharge and circulation of flue gas. Here, the flue gas network includes the flues connecting each device and valves provided on the flues, etc.

[0032] The temperature of the first sintering flue gas after the first heating is the first temperature. The first temperature can be specifically determined according to needs. Preferably, the first temperature is a temperature above 600 - 700 °C. That is, preferably, the first sintering flue gas is heated to above 600 - 700 °C. During the process of the first sintering flue gas being heated for the first time, CO in the first sintering flue gas reacts with oxygen and is partially or completely removed.

[0033] The temperature of the first sintering flue gas after being reheated for the second time is the second temperature. The second temperature is specifically determined as needed, as long as it ensures sufficient reaction between carbon monoxide and oxygen. The second temperature is preferably 650-900 °C. If not all of the CO is eliminated when the first sintering flue gas is heated for the first time, the remaining CO will be fully reacted with oxygen during the second heating process and thus eliminated.

[0034] Operating principle of the system for eliminating CO in sintering flue gas:

[0035] The system for eliminating CO in sintering flue gas can be installed on the existing sintering flue gas emission system for use. Alternatively, based on this system for eliminating CO in sintering flue gas, other purification treatment systems can be added to form an independent emission system, directly comprehensively treating the sintering flue gas generated by the sintering machine and then discharging it.

[0036] Taking the installation in the existing sintering flue gas emission system as an example for illustration, in the existing sintering flue gas emission system, after the sintering flue gas is generated in the sintering machine 101, it will successively pass through the desulfurization system 102, the dust removal system 103, and the denitrification system 104 for purification treatment, and finally be discharged through the smoke exhaust chimney 106 under the power provided by the main exhaust fan 105.

[0037] In order to make the CO concentration in the flue gas finally discharged through the smoke exhaust chimney 106 meet the emission standards, the system for eliminating CO in the sintering flue gas can be installed. The main intake flue of the system for eliminating CO in the sintering flue gas is used to obtain the first sintering flue gas, that is, the sintering flue gas generated by the sintering machine. When obtaining the sintering flue gas, the amount of sintering flue gas obtained can be determined according to different emission standards. That is to say, a part of the sintering flue gas can be obtained for CO reduction treatment; the remaining part is not subjected to CO reduction treatment and is treated by the original emission system. After that, the sintering flue gas that has undergone CO reduction treatment is mixed with the sintering flue gas that has not undergone CO reduction treatment and discharged through the smoke exhaust chimney 106, and the CO concentration of the mixed sintering flue gas meets the emission standards. The proportion of the first sintering flue gas obtained in the sintering flue gas generated by the sintering machine 101 can be specifically determined according to different emission standards. For example, all the sintering flue gas generated by the sintering machine 101 can be obtained, or 90%, 80%... of the flue gas generated by the sintering machine 101 can be obtained for CO reduction treatment. The gas extraction position can also be determined as needed. Specifically, gas can be extracted through the main intake flue 111. The extraction proportion of the sintering flue gas can be adjusted by the valve at the main intake flue 111 to adjust the extraction proportion of the sintering flue gas. The gas extraction position is determined by the connection position of the main intake flue 111. Among them, the main intake flue 111 can be connected to a certain position at the inlet or outlet of any flue gas purification system such as the desulfurization system 102, the dust removal system 103, the denitration system 104, and the main exhaust fan 105. Similarly, the main exhaust flue 112 can also be connected to a certain position at the inlet or outlet of any flue gas purification system such as the desulfurization system 102, the dust removal system 103, the denitration system 104, and the main exhaust fan 105. See Figure 2 , the main intake flue 111 is connected to the outlet position of the main exhaust fan; the main exhaust flue 112 is directly connected to the smoke exhaust chimney 106, which is equivalent to being connected to the position at the outlet of the main exhaust fan 105. See Figure 3 , the main intake flue 111 is connected to the outlet position of the dust removal system 103; the main exhaust flue 112 is also connected to the outlet position of the dust removal system 103. See Figure 1 , the main intake flue 111 can also be directly connected to the sintering air box in the sintering machine where the CO concentration is greater than the first preset value, that is, only the sintering flue gas discharged from the sintering air box with a CO concentration greater than the first preset value is subjected to CO reduction treatment. In this case, the purification system 9 can be set to first purify the obtained first sintering flue gas, such as desulfurization, dust removal, denitration, etc., and then introduce the first sintering flue gas into the heat exchanger 1 for CO elimination treatment.

[0038] After the first sintering flue gas enters through the main intake flue 111, it first enters the heat exchanger 1, and one or more groups of heat exchangers 1 can be provided. The heat exchanger 1 has two intake ports, a first intake port and a second intake port; and two outlet ports, a first outlet port and a second outlet port. The first sintering flue gas enters the heat exchanger 1 through the first intake port, absorbs heat during the process of flowing through the heat exchanger 1, and is heated for the first time (this heat comes from the heat released by the second flue gas formed by the mixing of the first sintering flue gas and the first flue gas in the previous time period), and then flows out through the first outlet port and into the mixing chamber 3. At the same time, the blast furnace gas and the combustion-supporting gas are burned in the hot blast stove 2 to obtain the first flue gas, and the first flue gas also enters the mixing chamber 3 and is mixed with the first sintering flue gas. Since the temperature of the first flue gas is relatively high, the first sintering flue gas will be heated for the second time during the mixing process. Here, the gas that fully eliminates CO after the mixing of the first sintering flue gas and the first flue gas is called the second flue gas. During the first heating process of the first sintering flue gas, CO reacts with oxygen and is partially or completely eliminated. During the second heating process, it is used to supplement heat to heat the first sintering flue gas newly entering the heat exchanger 1 for the first time, and when CO is not completely eliminated, the remaining CO is further eliminated. The second flue gas enters through the second intake port of the heat exchanger 1 and releases heat during the process of flowing through the heat exchanger 1 (this part of the heat is finally absorbed by the first sintering flue gas newly entering the heat exchanger 1 from the first intake port). The CO concentration in the second flue gas after releasing heat is relatively low, and it can be directly discharged into the exhaust chimney 106, or it can be discharged into the exhaust chimney 106 after subsequent treatment. Among them, when the first sintering flue gas enters from the first intake port of the heat exchanger 1 and flows through the heat exchanger 1, its temperature gradually rises. The first sintering flue gas is heated to a preset temperature, such as 600 - 700 °C or above, only when it flows to the first outlet port of the heat exchanger 1.

[0039] It should be noted that: continuously newly obtained first sintering flue gas enters the heat exchanger 1, is mixed with the first flue gas to form the second flue gas, and then flows through the heat exchanger 1 again to heat the first sintering flue gas newly entering the heat exchanger 1 for the first time. The second flue gas and the first sintering flue gas do not mix with each other in the heat exchanger 1.

[0040] The utility model generates high-temperature first flue gas by burning blast furnace gas and combustion-supporting flue gas through the setting of a hot blast stove, and the sintering flue gas to be treated (the first sintering flue gas) is first heated through the setting of a self-coupling heat exchanger. Then, the first flue gas is mixed with the first sintering flue gas after the first heating, and during the mixing process with the high-temperature first flue gas, the first sintering flue gas is secondarily heated. During the two heating processes, CO in the first sintering flue gas fully reacts with oxygen and is thus eliminated. At this time, the mixed gas of the first sintering flue gas and the first flue gas (the second flue gas) still has a relatively high temperature. The second flue gas is introduced into the self-coupling heat exchanger for heat release, and the released heat is used for the first heating of the first sintering flue gas. Thereby, it replaces the method of catalytic oxidation of CO with a catalyst in the prior art to eliminate CO in the sintering flue gas. At the same time, the heat of the second flue gas is fully utilized, saving energy consumption. Thus, it is possible to completely not use a catalyst, or only use a relatively small amount of catalyst to complete the elimination of CO. Compared with the prior art that requires frequent catalyst replacement, it can not only reduce costs but also avoid problems such as shutdown caused by catalyst replacement.

[0041] Optionally, the combustion-supporting gas is a part of the first sintering flue gas. The flue gas network includes a first flue with a first end connected to the hot blast stove, and the first flue is used to introduce a part of the first sintering flue gas; a combustion-supporting fan may be provided on the first flue.

[0042] Alternatively, the combustion-supporting gas is a part of the second flue gas that has not flowed through the heat exchanger. The flue gas network includes a second flue with a first end connected to the hot blast stove, and the second flue is used to introduce a part of the second flue gas that has not flowed through the heat exchanger; a combustion-supporting fan may be provided on the second flue.

[0043] Alternatively, the combustion-supporting gas is a part of the second flue gas after heat release in the heat exchanger. The flue gas network includes a third flue 113 with a first end connected to the hot blast stove, and the third flue 113 is used to introduce a part of the second flue gas after heat release in the heat exchanger; a combustion-supporting fan may be provided on the third flue.

[0044] Alternatively, the combustion-supporting gas is air. The flue gas network includes a fourth flue with a first end connected to the hot blast stove, and the fourth flue is used to introduce external air. A combustion-supporting fan may be provided on the fourth flue.

[0045] Optionally, referring to Figure 1 , it further includes a starting heat source 8. The starting heat source 8 is used to burn natural gas and the combustion-supporting gas to generate a third flue gas during the starting stage. Similarly, during the starting stage, the mixing chamber 3 is used to mix the first flue gas, the third flue gas, and the first sintering flue gas after the first heating to secondarily heat the first sintering flue gas, thereby obtaining the second flue gas.

[0046] When the system for eliminating CO in sintering flue gas is just started, since the heat provided by the hot blast stove is less, when the first sintering flue gas flows through the heat exchanger and is heated for the first time, it cannot absorb much heat. After being heated for the first time, its temperature is still relatively low, and the temperature of the second flue gas formed after mixing with the first flue gas is also relatively low. Therefore, the heat released by the second flue gas is less, and the released heat is used to conduct the first heating of the newly entered first sintering flue gas, and so on in a cycle. The temperature of the second flue gas is a process of gradually rising temperature, the heat released by the second flue gas is also a process of gradually increasing, and the temperature of the first sintering flue gas after being heated for the first time is also a process of gradually rising temperature. This process is called the start-up stage of the system. After the start-up stage, the second flue gas can maintain a relatively high temperature to conduct the first heating of the first sintering flue gas. The temperature of the first sintering flue gas after the first heating is relatively high, and after mixing with the first flue gas, it can reach a higher temperature, enabling CO to fully react with oxygen. During the entire start-up stage, the heat mainly comes from the first flue gas generated by the hot blast stove 2, and the start-up stage takes a relatively long time.

[0047] In order to reduce the time of the start-up stage, a start-up heat source 8 can be added. The start-up heat source 8 is enabled during the start-up stage and can stop working after the start-up stage. The start-up heat source 8 is used to burn natural gas and combustion-supporting gas to generate a third flue gas, and the third flue gas is introduced into the mixing chamber 3 so that the third flue gas, the first flue gas, and the first sintering flue gas are mixed in a certain proportion to conduct the second heating of the first sintering flue gas. The second flue gas during the start-up stage is composed of the first flue gas, the third flue gas, and the first sintering flue gas. After a period of time, after the first sintering flue gas newly entering the heat exchanger 1 can reach the preset value after being heated for the first time, the start-up heat source 8 can be turned off.

[0048] In addition, the gas pipeline required for natural gas is relatively thin, which can reduce the laying cost of the gas pipeline. Specifically, the third flue gas, the first flue gas, and the first sintering flue gas can be mixed in a certain proportion to form a second flue gas to conduct the first heating of the newly obtained first sintering flue gas. During the start-up stage, compared with the first sintering flue gas in the previous round (the first sintering flue gas obtained in the previous period of time), the temperature of the newly obtained first sintering flue gas (the first sintering flue gas obtained in the subsequent period of time) after being heated for the first time gradually increases. When the temperature reached by the first sintering flue gas after being heated for the first time is greater than or equal to the standard value, the start-up stage ends, and at this time, the generation of the third flue gas can be stopped. Increasing the third flue gas can reduce the time of the start-up stage.

[0049] Optionally, the flue gas network includes a main intake flue 111 and a main exhaust flue 112, and the power device includes a main control fan 4. The main control fan 4 is arranged at the main intake flue 111 or the main exhaust flue 112.

[0050] Figures 1-3Shown is the case where the main control fan 4 is provided at the main exhaust flue 112.

[0051] Optionally, it further includes a gas preheater 5 for preheating blast furnace gas. The gas preheater 5 is respectively connected to the heat exchanger 1 and the hot blast stove 2. The gas preheater 5 is used for heat exchange between the second flue gas after the heat exchanger 1 releases heat and the blast furnace gas.

[0052] After the second flue gas releases heat in the heat exchanger 1, it still has a temperature higher than that of the blast furnace gas. In order to further utilize this part of the heat, the gas preheater 5 is added. The gas preheater 5 includes two flues. One flue is used for the flow of the second flue gas, and the other flue is used for the flow of the blast furnace gas. The second flue gas releases heat when flowing through the gas preheater 5, and the blast furnace gas absorbs heat when flowing through the gas preheater 5.

[0053] Optionally, the combustion-supporting gas is a part of the second flue gas after the heat exchanger 1 releases heat. The flue gas network includes a third flue 113. The first end of the third flue 113 is connected to the hot blast stove 2, and the second end of the third flue 113 is connected to the position of the main exhaust flue 112; the power device includes a main control fan 4 and a combustion-supporting fan 7; the main control fan 4 is provided on the main exhaust flue 112, and the combustion-supporting fan 7 is provided on the third flue 113.

[0054] Under the action of the combustion-supporting fan 7, a part of the second flue gas at the position of the main exhaust flue 112 will enter the third flue 113 and finally flow into the hot blast stove 2 as the combustion-supporting gas to burn with the blast furnace gas.

[0055] A gas desulfurization device 6 can also be provided between the gas preheater 5 and the hot blast stove 2.

[0056] Some blast furnace gases have a high sulfur content. After passing through the gas preheater 5, they can reach the desulfurization temperature. After adding the gas desulfurization device 6, the blast furnace gas can be desulfurized to prevent the SO2 emission concentration from exceeding the standard.

[0057] Optionally, the heat exchanger includes one or more of a switching regenerative heat exchanger, a rotary regenerative heat exchanger, a plate heat exchanger, a tubular heat exchanger, and a heat pipe heat exchanger.

[0058] Figures 1-3Shown is a case where a regenerative heat exchanger is used as heat exchanger 1. The regenerative heat exchanger includes two regenerators 11 connected in series. A reversing valve group 12 is provided on the regenerator 11, and the flue gas flow direction is switched according to a certain period. Here, the two regenerators 11 are respectively referred to as regenerator A and regenerator B for explanation. The original low-temperature CO-containing sintering flue gas to be reduced (the first sintering flue gas) enters regenerator A from the inlet of regenerator A. In regenerator A, the CO-containing sintering flue gas to be reduced is heated to 600 - 700 °C or higher by the relatively high-temperature heat storage body. During this process, part or all of the CO reacts with oxygen and is eliminated. The CO-containing sintering flue gas to be reduced after being heated in regenerator A then leaves regenerator A and is mixed with the high-temperature flue gas (the first flue gas) from the hot blast stove 2 to be heated to 650 - 900 °C. The remaining CO in the heated sintering flue gas is fully oxidized and eliminated to form a high-temperature CO-free sintering flue gas (the second flue gas). The high-temperature CO-free sintering flue gas then enters regenerator B to release heat to the heat storage body B to form a low-temperature CO-free sintering flue gas. After leaving regenerator B, the low-temperature CO-free sintering flue gas is discharged into the atmosphere through the gas preheater 5, the main control fan 4, and the exhaust chimney 106. At the next moment, the new CO-containing sintering flue gas to be reduced enters and exits regenerator B in the opposite direction, is mixed with the high-temperature flue gas from the hot blast stove 2, and then flows into regenerator A. After flowing out of regenerator A, it flows through the gas preheater 5 and the main control fan 4, and finally is discharged into the atmosphere through the exhaust chimney 106.

[0059] Rotary regenerative heat exchangers, plate heat exchangers, tubular heat exchangers, and heat pipe heat exchangers are all existing heat exchangers, and their working principles will not be described in detail here.

Claims

1. A system for removing CO from sintering flue gas, characterized in that, Comprising: A hot blast stove for burning blast furnace gas and combustion-supporting gas to obtain a first flue gas; A heat exchanger for the second flue gas to release heat and for the first sintering flue gas to be heated for the first time; the first sintering flue gas is the sintering flue gas from which CO is to be removed; the second flue gas after releasing heat in the heat exchanger is the flue gas to be discharged; A mixing chamber for mixing the first flue gas with the first sintering flue gas after the first heating to heat the first sintering flue gas for the second time, thereby obtaining the second flue gas; A power device for providing power for the flow of the flue gas; A flue gas network for connecting the hot blast stove, the heat exchanger, the mixing chamber and the power device to allow the flue gas to enter, discharge and circulate.

2. The system for removing CO from sintering flue gas according to claim 1, characterized in that The combustion-supporting gas is a part of the first sintering flue gas, and the flue gas network includes a first flue with a first end connected to the hot blast stove, and the first flue is used for introducing a part of the first sintering flue gas; Or, the combustion-supporting gas is a part of the second flue gas that has not flowed through the heat exchanger, and the flue gas network includes a second flue with a first end connected to the hot blast stove, and the second flue is used for introducing a part of the second flue gas that has not flowed through the heat exchanger; Or, the combustion-supporting gas is a part of the second flue gas after releasing heat in the heat exchanger, and the flue gas network includes a third flue with a first end connected to the hot blast stove, and the third flue is used for introducing a part of the second flue gas after releasing heat in the heat exchanger; Or, the combustion-supporting gas is air, and the flue gas network includes a fourth flue with a first end connected to the hot blast stove, and the fourth flue is used for introducing external air.

3. The system for removing CO from sintering flue gas according to claim 1, characterized in that, It further includes a starting heat source for burning natural gas and combustion-supporting gas to generate a third flue gas during the starting stage; The mixing chamber is used for mixing the first flue gas, the third flue gas and the first sintering flue gas after the first heating during the starting stage to heat the first sintering flue gas for the second time, thereby obtaining the second flue gas.

4. The system for removing CO in sintering flue gas according to claim 1, wherein, The flue gas network includes a main intake flue and a main exhaust flue, and the power device includes a main control fan, and the main control fan is arranged at the main intake flue or the main exhaust flue.

5. The system for removing CO in sintering flue gas according to claim 1, characterized in that, It further includes a gas preheater for preheating the blast furnace gas, and the gas preheater is respectively connected to the heat exchanger and the hot blast stove, and the gas preheater is used for heat exchange between the second flue gas after releasing heat in the heat exchanger and the blast furnace gas.

6. The system for removing CO in sintering flue gas according to claim 5, characterized in that, The combustion-supporting gas is a part of the second flue gas after releasing heat in the heat exchanger, and the flue gas network includes a third flue, the first end of the third flue is connected to the hot blast stove, and the second end of the third flue is connected to the position of the main exhaust flue; the power device includes a main control fan and a combustion-supporting fan; the main control fan is arranged on the main exhaust flue, and the combustion-supporting fan is arranged on the third flue; Or, a gas desulfurization device is further arranged between the gas preheater and the hot blast stove.

7. The system for removing CO in sintering flue gas according to claim 1, characterized in that, The heat exchanger includes one or more of a switching regenerative heat exchanger, a rotary regenerative heat exchanger, a plate heat exchanger, a tubular heat exchanger, and a heat pipe heat exchanger.

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