A blast furnace hot blast stove synchronous desulfurization and denitrification system and process

Abstract

The present invention provides a system and process for synchronous desulfurization and denitrification of a blast furnace hot blast furnace. The system comprises a blast furnace hot blast furnace, an ammonia zone, an SCR denitrification reactor, a hot blast furnace heat exchanger, a desulfurizer powder silo, a dust collector, a first induced draft fan, and a chimney. The flue gas outlet of the blast furnace hot blast furnace and the ammonia zone are connected to the flue gas inlet of the SCR denitrification reactor via an inlet flue and an ammonia supply pipeline, respectively. The flue gas outlet is connected to the inlet of the hot blast furnace heat exchanger via an outlet flue. The outlet of the hot blast furnace heat exchanger is connected to the inlet of the dust collector via an outlet flue through a desulfurizer powder silo. The clean flue gas outlet is connected to the chimney via the outlet flue through a first induced draft fan. While purifying the blast furnace hot blast furnace flue gas, the present invention also enables 100% synchronous operation of the desulfurization and denitrification process with the main hot blast furnace process. The desulfurization and denitrification equipment can be maintained online, eliminating the problem of blast furnace production being affected by the installation of desulfurization and denitrification equipment and reducing the investment and operating costs of desulfurization and denitrification.

Description

Technical Field

[0001] The present invention relates to a system and process for synchronous desulfurization and denitrification of a blast furnace hot blast stove, belonging to the technical field of flue gas desulfurization and denitrification. Background Art

[0002] Chinese steel companies mainly use long process technology. The blast furnace ironmaking systems they use are all equipped with hot blast stoves. Usually, one blast furnace is equipped with 3-4 hot blast stoves. The hot blast stoves use blast furnace gas as fuel. Since the gas contains sulfur, the SO2 concentration in the flue gas after gas combustion is usually 80-150mg / Nm 3 In addition, since the hot blast furnace combustion temperature is ≥1250℃, the gas combustion will also produce NOx, the concentration of which is 40-250mg / Nm 3 , and there are instantaneous high concentration conditions.

[0003] As environmental emission standards become increasingly stringent, some local standards require SO2, NOx and particulate matter emissions to reach 20mg / Nm 3 、50mg / Nm 3 and 8mg / Nm 3 .

[0004] In addition, the temperature before the hot blast furnace heat exchanger is relatively high, reaching 230-360°C, and the temperature after the heat exchanger is about 110-160°C. There will also be maintenance conditions, and high-temperature flue gas will be directly discharged.

[0005] Therefore, the selection of desulfurization and denitrification technology needs to comprehensively consider its impact on the hot blast stove itself, as well as its impact on the heat exchanger and coal injection; and consider the adaptability of the desulfurization and denitrification process to the flue gas temperature and process production system.

[0006] Prior art 1 related to the present invention:

[0007] Technical solution of prior art 1:

[0008] Existing technology 1, namely Zhou Xia, Zhou Jiping, and Han Jiayou. Analysis of ultra-low emission upgrade and transformation plan for flue gas desulfurization of Meigang No. 2 blast furnace hot blast furnace [J]. Energy Conservation and Environmental Protection, 2022(3):3. A dry process for desulfurization of blast furnace hot blast furnace flue gas using a calcium-based fixed bed is mentioned, which uses an active calcium hydroxide desulfurizer to absorb SO2 in the flue gas.

[0009] Disadvantages of the prior art 1:

[0010] The fixed bed desulfurizer used in the prior art is granular and adopts dry desulfurization. The desulfurizer is not fully utilized and the reaction in the inner layer of the particles is incomplete, resulting in a large consumption of desulfurizer and a corresponding large amount of solid waste. In addition, the desulfurization by-product is still a mixture containing a large amount of desulfurizer components.

[0011] The second prior art related to the present invention:

[0012] Technical solution of existing technology 2:

[0013] Chinese patent CN 213286312 U discloses a desulfurization and denitrification device based on a calcium-based absorbent and a fixed bed, which uses a fixed bed to carry out a process of desulfurization and denitrification of blast furnace hot blast stove flue gas, and removes oxidized SO2 and NOx in the flue gas through a calcium-based absorbent.

[0014] Disadvantages of the second prior art:

[0015] The fixed bed calcium-based absorbent used in the second prior art is in the form of long strips, and uses dry desulfurization and denitrification, resulting in large absorbent consumption and corresponding large amounts of solid waste. In addition, the fixed bed denitrification uses ClO2 oxidation, which has high oxidant costs and introduces a large amount of NO3 into the by-products. - 、Cl - , resulting in the inability to effectively utilize by-products. Therefore, the fixed bed denitrification efficiency is not high and it is difficult to meet emission targets.

[0016] The third prior art related to the present invention:

[0017] Technical solution of existing technology three:

[0018] The third prior art, namely, Erdemutu, Xin Cheng, Gao Qiuting. Application of sodium-based dry desulfurization process in blast furnace hot blast stove flue gas desulfurization [J] Chemical Engineering Design Communications, Vol. 48, No. 5, mentions an SDS sodium-based dry desulfurization, which grinds the desulfurizer for desulfurization; Chinese patent CN 211936312 U discloses a blast furnace hot blast stove exhaust gas desulfurization and denitrification system, which adopts SDS dry desulfurization, and denitrification adopts a catalyst installed above the dust collector, first desulfurization and then heating and denitrification.

[0019] Disadvantages of the existing technology three:

[0020] The SDS dry desulfurization used in the third existing technology adopts bags as dust collector filter materials, but does not take into account high-temperature maintenance conditions; denitrification requires additional hot air for heating, which consumes high energy; the low-temperature catalyst used needs to consider life and regeneration, which affects the production of the hot blast furnace.

[0021] Therefore, providing a new type of blast furnace hot blast stove synchronous desulfurization and denitrification system and process has become a technical problem that needs to be solved urgently in this field. Summary of the Invention

[0022] In order to solve the above-mentioned shortcomings and deficiencies, one object of the present invention is to provide a blast furnace hot blast stove synchronous desulfurization and denitrification system.

[0023] Another object of the present invention is to provide a process for simultaneous desulfurization and denitrification of a blast furnace hot blast stove.

[0024] In order to achieve the above objectives, on the one hand, the present invention provides a blast furnace hot blast stove synchronous desulfurization and denitrification system, wherein the blast furnace hot blast stove synchronous desulfurization and denitrification system comprises:

[0025] Blast furnace hot blast stove, ammonia zone, SCR denitrification reactor, hot blast stove heat exchanger, desulfurizer powder silo, dust collector, first induced draft fan and chimney;

[0026] The flue gas outlet of the blast furnace hot blast stove and the ammonia zone are respectively connected to the flue gas inlet of the SCR denitrification reactor through the inlet flue and the ammonia supply pipeline. The flue gas outlet of the SCR denitrification reactor is connected to the inlet of the hot blast stove heat exchanger through the outlet flue. The outlet of the hot blast stove heat exchanger is connected to the inlet of the dust collector through the outlet flue via the desulfurizer powder bin. The clean flue gas outlet of the dust collector is connected to the chimney through the outlet flue via the first induced draft fan.

[0027] As a specific embodiment of the above-mentioned simultaneous desulfurization and denitrification system for a blast furnace hot blast stove of the present invention, an ammonia injection device is provided on the inlet flue, and the ammonia injection device is connected to the ammonia zone through an ammonia supply pipeline.

[0028] As a specific embodiment of the above-mentioned blast furnace hot blast stove synchronous desulfurization and denitrification system of the present invention, the ammonia zone can use liquid ammonia, ammonia water or urea as a denitrification reducing agent.

[0029] As a specific embodiment of the above-mentioned blast furnace hot blast stove synchronous desulfurization and denitrification system of the present invention, wherein the SCR denitrification reactor is arranged in a chamber, which includes a denitrification inlet smoke box and multiple SCR denitrification reaction chambers, and the multiple outlets of the denitrification inlet smoke box are respectively connected to the multiple SCR denitrification reaction chambers through denitrification inlet valve groups, and the flue gas outlets of the multiple SCR denitrification reaction chambers are respectively provided with denitrification outlet valve groups;

[0030] Alternatively, the SCR denitration reactor is a single-chamber structure, and no valves are provided at its inlet and outlet.

[0031] In the synchronous desulfurization and denitrification system for the blast furnace hot blast stove provided by the present invention, the flue gas inlet and flue gas outlet of each chamber in the SCR denitrification reactor are respectively provided with a denitrification inlet valve group and a denitrification outlet valve group. By controlling the denitrification inlet valve group and the denitrification outlet valve group, the SCR denitrification reactor can be realized online and offline, thereby realizing online maintenance and online catalyst replacement.

[0032] As a specific embodiment of the above-mentioned blast furnace hot blast stove synchronous desulfurization and denitrification system of the present invention, wherein the inlet flue and outlet flue of the hot blast stove heat exchanger are respectively provided with a heat exchanger inlet valve and a heat exchanger outlet valve;

[0033] The hot blast stove heat exchanger is also provided with a first heat regeneration flue, which connects the flue before the heat exchanger inlet valve and the flue after the heat exchanger and before the heat exchanger outlet valve, and is provided with a first heat regeneration valve;

[0034] The hot blast stove heat exchanger is also provided with a second heat regeneration flue, which connects the flue after the heat exchanger inlet valve and in front of the heat exchanger and the flue after the heat exchanger outlet valve, and is provided with a second heat regeneration valve.

[0035] As a specific embodiment of the synchronous desulfurization and denitrification system for the blast furnace hot blast stove of the present invention, the hot blast stove heat exchanger is also provided with a heat exchanger bypass flue, which connects the flue before the heat exchanger inlet valve and the flue after the heat exchanger outlet valve, and a heat exchanger bypass valve is provided on it.

[0036] As a specific embodiment of the above-mentioned synchronous desulfurization and denitrification system for the blast furnace hot blast stove of the present invention, the desulfurizer powder bin is connected to the outlet flue of the hot blast stove heat exchanger through an injection pipeline via an injection device.

[0037] As a specific embodiment of the synchronous desulfurization and denitrification system for the blast furnace hot blast stove of the present invention, a flue reactor is provided on the outlet flue of the hot blast stove heat exchanger, and the desulfurizer powder bin is connected to the flue reactor via an injection pipeline via an injection device.

[0038] As a specific embodiment of the above-mentioned simultaneous desulfurization and denitrification system for a blast furnace hot blast stove of the present invention, the injection device may be, for example, a conveying fan.

[0039] As a specific embodiment of the synchronous desulfurization and denitrification system for the blast furnace hot blast stove of the present invention, a cooling device is provided on the flue between the desulfurizer powder bin and the dust collector (for the hot blast stove heat exchanger, the flue is the outlet flue, and for the dust collector, the flue is the inlet flue).

[0040] As a specific embodiment of the above-mentioned simultaneous desulfurization and denitrification system for a blast furnace hot blast stove of the present invention, the cooling device includes a cold air valve, a cooling water spray gun or a water spray cooling valve group, etc.

[0041] The present invention provides a cooling device at the inlet of the dust collector to cope with high temperature conditions during maintenance of the hot blast furnace heat exchanger, thereby avoiding damage to the filter bags of the dust collector and ensuring the safety of the dust collector.

[0042] As a specific embodiment of the above-mentioned blast furnace hot blast stove synchronous desulfurization and denitrification system of the present invention, the dust collector uses high-temperature resistant cloth bags.

[0043] As a specific embodiment of the above-mentioned blast furnace hot blast stove synchronous desulfurization and denitrification system of the present invention, wherein the system further includes a second induced draft fan, and the clean flue gas outlet of the dust collector is connected to the chimney through the outlet flue in sequence via the first induced draft fan inlet valve, the first induced draft fan and the first induced draft fan outlet valve;

[0044] The clean flue gas outlet of the dust collector is also connected to the chimney through the outlet flue in sequence via the second induced draft fan inlet valve, the second induced draft fan and the second induced draft fan outlet valve.

[0045] The present invention provides valves at the inlet and outlet of the first induced draft fan and the second induced draft fan respectively, which can ensure that when one induced draft fan is under maintenance, the other can continue to be used, so that the hot blast furnace system can still work normally.

[0046] When two induced draft fans, i.e., a first induced draft fan and a second induced draft fan, are provided in the synchronous desulfurization and denitrification system for the blast furnace hot blast stove provided by the present invention, the two induced draft fans can be configured with one in use and the other in standby at full load. When one induced draft fan fails, the inlet valve and the outlet valve of the induced draft fan are closed for maintenance, and the other is started to ensure the availability of the system. During normal operation, the machines can also be reversed regularly; or the two induced draft fans can be configured with half load as standby for each other.

[0047] As a specific embodiment of the synchronous desulfurization and denitrification system for the blast furnace hot blast stove of the present invention, the dust collector is arranged in chambers, and the inlet and outlet of each chamber of the dust collector are respectively provided with a dust collector inlet valve and a dust collector outlet valve, and an ash conveying system, such as a pneumatic conveying system, is provided under the dust collector, and the ash conveying system is connected to the by-product bin.

[0048] The present invention provides a dust collector inlet valve and a dust collector outlet valve at the inlet and outlet of each dust collector chamber respectively, thereby realizing offline and online operation of the dust collector chamber, thereby realizing online maintenance and online filter bag replacement.

[0049] On the other hand, the present invention also provides a blast furnace hot blast stove synchronous desulfurization and denitrification process, wherein the blast furnace hot blast stove synchronous desulfurization and denitrification process comprises:

[0050] (1) The flue gas from the blast furnace hot blast stove outlet is directly sent to the SCR denitrification reactor. In the SCR denitrification reactor, the NOx in the flue gas reacts with the denitrification reducing agent sent from the ammonia zone under the action of the SCR catalyst to complete the denitrification;

[0051] (2) The high-temperature flue gas after denitrification enters the hot air furnace heat exchanger to recover heat and obtain cooled flue gas;

[0052] (3) The cooled flue gas reacts with the desulfurizer sprayed from the desulfurizer powder bin in the outlet flue to complete the desulfurization;

[0053] (4) The flue gas after desulfurization carries a large amount of by-product powder into the dust collector and undergoes gas-solid separation to obtain clean flue gas and by-products. The clean flue gas is sucked by the induced draft fan and sent to the chimney for discharge. At the same time, the by-products separated by the dust collector are sent to the by-product bin.

[0054] As a specific embodiment of the above-mentioned blast furnace hot blast stove simultaneous desulfurization and denitrification process of the present invention, when liquid ammonia is used as a denitrification reducing agent in the ammonia zone, the liquid ammonia is first evaporated through a liquid ammonia evaporator, and then the obtained ammonia gas is sent to the SCR denitrification reactor;

[0055] When ammonia water is used as a denitrification reducing agent, the ammonia water is first sent to the vicinity of the SCR denitrification reactor, and high-temperature flue gas is introduced into the ammonia water evaporator to evaporate it, and then the resulting ammonia gas is sent to the SCR denitrification reactor;

[0056] When urea is used as a denitrification reducing agent, it can be decomposed first, or it can be directly sprayed into a high-temperature flue for decomposition and then sent to an SCR denitrification reactor; it can also be diluted first and then nitrogen atomized before being sprayed into an SCR denitrification reactor.

[0057] The SCR catalysts used in the present invention are conventional catalysts used in the art and are commercially available. During implementation, a specific SCR catalyst can be reasonably selected based on actual on-site operational needs.

[0058] As a specific embodiment of the above-mentioned simultaneous desulfurization and denitrification process for blast furnace hot blast stoves of the present invention, during normal system operation, the denitrification inlet valve group and the denitrification outlet valve group of the SCR denitrification reactor are always open, and the flue gas passes through each chamber in the SCR denitrification reactor; when it is necessary to remove the SCR catalyst test block or to inspect or replace the SCR catalyst, the denitrification inlet valve group and the denitrification outlet valve group of the corresponding chamber are closed, and the temperature is cooled before the corresponding operation is carried out. During this process, the blast furnace hot blast stove can continue production. In addition, when the high temperature of the blast furnace hot blast stove fluctuates, the SCR catalyst also has a high-temperature regeneration effect.

[0059] As a specific embodiment of the above-mentioned simultaneous desulfurization and denitrification process for a blast furnace hot blast stove of the present invention, when the system is operating normally, the heat exchanger inlet valve and the heat exchanger outlet valve of the hot blast stove heat exchanger are normally open, and the heat exchanger bypass valve, the first thermal regeneration valve, and the second thermal regeneration valve are normally closed. When the cold end of the hot blast stove heat exchanger is scaled due to low temperature, such as ammonium sulfate deposition, the process further includes thermal regeneration of the hot blast stove heat exchanger, and the thermal regeneration includes:

[0060] Close the heat exchanger inlet valve, heat exchanger outlet valve and heat exchanger bypass valve, open the first heat regeneration valve and the second heat regeneration valve, so that the hot flue gas enters from the cold end of the hot blast furnace heat exchanger and is discharged from the hot end, so that the scale on the cold end, such as ammonium sulfate, is decomposed at high temperature, completing the regeneration of the hot blast furnace heat exchanger.

[0061] In addition, during regeneration, the gas supply to the blast furnace hot blast stove can be increased to appropriately increase the flue gas temperature.

[0062] As a specific embodiment of the above-mentioned simultaneous desulfurization and denitrification process for a blast furnace hot blast stove of the present invention, when the temperature of the desulfurization process is ≤130°C, the process further comprises:

[0063] Partially open the bypass valve of the heat exchanger to mix the high-temperature flue gas with the low-temperature flue gas after passing through the hot blast furnace heat exchanger, so that the system temperature reaches the temperature required for desulfurization.

[0064] As a specific embodiment of the above-mentioned blast furnace hot blast stove synchronous desulfurization and denitrification process of the present invention, the desulfurizer is fed through the desulfurizer powder bin, then ground into 600-1000 mesh fine powder, and sprayed into the desulfurization flue or desulfurization flue reactor through a conveying fan.

[0065] As a specific embodiment of the above-described simultaneous desulfurization and denitrification process for a blast furnace hot blast stove of the present invention, when the flue gas temperature at the dust collector inlet exceeds the temperature resistance of the dust collector filter bags, a cooling device is activated to cool the flue gas. Specifically, when the cooling device is a cold air valve, the flue gas is cooled by the cold air supplied by the cold air valve. When the cooling device is a cooling water spray gun, the flue gas is cooled by spraying water through an atomizing spray gun.

[0066] As a specific embodiment of the above-mentioned simultaneous desulfurization and denitrification process for blast furnace hot blast stoves of the present invention, the desulfurizer is used once, and the desulfurization by-products formed are discharged into the by-product bin through a pneumatic conveying system.

[0067] As a specific implementation method of the synchronous desulfurization and denitrification process for blast furnace hot blast stoves described above in the present invention, when two induced draft fans, namely the first induced draft fan and the second induced draft fan, are used in the process, when the two are configured with one in use and one in standby at full load, during normal operation, one induced draft fan is turned on and the other is offline on standby; when the two are configured with 50% load as standby for each other, during normal operation, the two induced draft fans are turned on at the same time and are online standby for each other. When one induced draft fan fails, the other induced draft fan can meet the load reduction production of the blast furnace hot blast stove.

[0068] As a specific embodiment of the above-mentioned simultaneous desulfurization and denitrification process for the blast furnace hot blast stove of the present invention, the temperature range of the flue gas at the outlet of the hot blast stove is 230-360°C, and the temperature range of the flue gas after the hot blast stove heat exchanger is 110-160°C.

[0069] Compared with the existing technology, the blast furnace hot blast stove synchronous desulfurization and denitrification system and process provided by the present invention can achieve the following beneficial technical effects:

[0070] The synchronous desulfurization and denitrification system and process for the blast furnace hot blast stove provided by the present invention can perform equipment inspection and maintenance online by dividing the SCR denitrification reactor into compartments, dividing the dust collector into chambers, and setting a spare induced draft fan, thereby achieving 100% synchronization of desulfurization and denitrification with hot blast stove production, and desulfurization and denitrification no longer affect the normal production of the hot blast stove.

[0071] In the system provided by the present invention, the hot blast furnace heat exchanger is provided with a thermal regeneration valve group, which can greatly reduce the adverse effects of low-temperature adhesion scaling of the hot blast furnace heat exchanger, such as ammonium sulfate scaling, on the low-temperature end of the hot blast furnace heat exchanger, such as blockage, increased resistance loss, and reduced heat exchange efficiency, thereby improving the efficiency of the heat exchanger and extending the life of the equipment; at the same time, during thermal regeneration, the flue gas temperature exiting the hot blast furnace heat exchanger does not change significantly, and the dust collector bag will not be damaged due to high temperature.

[0072] In the system provided by the present invention, the hot blast furnace heat exchanger is also provided with a heat exchanger bypass flue and a heat exchanger bypass valve. Desulfurization and temperature increase can be achieved by controlling the heat exchanger bypass valve, thereby ensuring the desulfurization temperature requirement. In addition, desulfurization and temperature increase can also be achieved by increasing the combustion temperature of the hot blast furnace without the need for additional heating devices.

[0073] Compared to traditional denitrification systems, in the system provided by the present invention, the SCR denitrification reactor is located before the hot blast furnace heat exchanger, and there is no need to install a heating device (such as a heating furnace and GGH heat exchanger, etc.), which reduces equipment investment and system resistance, thereby saving electricity consumption; because there is no heating device, there is no need to burn blast furnace gas for heating, which correspondingly reduces equipment maintenance and eliminates the consumption of energy media such as gas; and desulfurization is carried out after heat exchange, so there is no need to install a heating device. In short, the system and process provided by the present invention have low investment and operating costs, simple operation and maintenance, and eliminate the adverse effects on hot blast furnace production.

[0074] In summary, the blast furnace hot blast stove synchronous desulfurization and denitrification system and process provided by the present invention removes SO2 and NOx from the flue gas generated by the blast furnace hot blast stove. While achieving blast furnace hot blast stove flue gas purification, it can also achieve 100% synchronous operation of the desulfurization and denitrification process and the hot blast stove main process. The desulfurization and denitrification equipment can be maintained online, solving the problem of blast furnace production being affected by the configuration of desulfurization and denitrification equipment, and also reducing the investment and operating costs of desulfurization and denitrification. On the basis of achieving flue gas desulfurization and denitrification emission standards, the operation and maintenance of the entire system can be made without affecting the operation of the blast furnace hot blast stove, and the risk of blockage of the blast furnace hot blast stove heat exchanger by ammonium sulfate and the like can be solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0076] Figure 1 This is a schematic structural diagram of the blast furnace hot blast stove synchronous desulfurization and denitrification system provided in Example 1 of the present invention.

[0077] Description of main figures:

[0078] 1- blast furnace hot blast furnace, 2- ammonia zone, 3- SCR denitrification reactor, 4- hot blast furnace heat exchanger, 5- desulfurizer powder silo, 6- cooling device, 7- dust collector, 8- by-product silo, 9- first induced draft fan, 10- second induced draft fan, 11- chimney; 31- denitrification inlet smoke box, 32- denitrification inlet valve group, 33- denitrification outlet valve group; 41- heat exchanger inlet valve, 42- heat exchanger outlet valve, 43- heat exchanger bypass valve, 44- first thermal regeneration valve, 45- second thermal regeneration valve; 91- first induced draft fan inlet valve, 92- first induced draft fan outlet valve, 101- second induced draft fan inlet valve, 102- second induced draft fan outlet valve. DETAILED DESCRIPTION

[0079] It should be noted that the term "comprise" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products or apparatus.

[0080] In the present invention, terms such as "upper," "lower," "inner," "outer," and "center" indicate positions or locations based on those shown in the accompanying drawings. These terms are intended primarily to better describe the present invention and its embodiments and are not intended to limit the devices, elements, or components indicated to specific positions, or to their construction or operation in a specific position.

[0081] Furthermore, some of the above technical terms may be used to express other meanings besides indicating a position or location. For example, the technical term "upper" may also be used to indicate a dependency or connection in certain circumstances. Those skilled in the art will understand the specific meanings of these technical terms in the present invention based on the specific circumstances.

[0082] Furthermore, the technical terms "disposed" and "connected" should be interpreted broadly. For example, "connected" can mean a fixed connection, a removable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediary, or it can be internal communication between two devices, elements, or components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances.

[0083] The "range" disclosed in the present invention is given in the form of a lower limit and an upper limit. It can be one or more lower limits, and one or more upper limits respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower limit and upper limit define the boundaries of a particular range. All ranges defined in this way are combinable, i.e., any lower limit can be combined with any upper limit to form a range. For example, a range of 60-120 and 80-110 is listed for a particular parameter, and it is understood that a range of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​listed are 1 and 2, and the maximum range values ​​listed are 3, 4, and 5, then the following ranges can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0084] In the present invention, unless otherwise specified, the numerical range "ab" is an abbreviation for any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" are listed in this invention, and "0-5" is merely an abbreviation for these numerical combinations.

[0085] In the present invention, unless otherwise specified, all embodiments and preferred embodiments mentioned in the present invention can be combined with each other to form a new technical solution.

[0086] In the present invention, unless otherwise specified, all technical features and preferred features mentioned in the present invention can be combined with each other to form a new technical solution.

[0087] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings and Examples. The following embodiments are part of the present invention, rather than all of the embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0088] Example 1

[0089] This embodiment provides a blast furnace hot blast stove synchronous desulfurization and denitrification system, the structural diagram of which is as follows: Figure 1 As shown, from Figure 1 As can be seen, the system includes:

[0090] The blast furnace hot blast furnace synchronous desulfurization and denitrification system comprises: a blast furnace hot blast furnace 1, an ammonia zone 2, an SCR denitrification reactor 3, a hot blast furnace heat exchanger 4, a desulfurizer powder bin 5, a dust collector 7, a first induced draft fan 9 and a chimney 11;

[0091] The flue gas outlet of the blast furnace hot blast stove 1 and the ammonia zone 2 are connected to the flue gas inlet of the SCR denitration reactor 3 through an inlet flue and an ammonia supply pipeline, respectively. The flue gas outlet of the SCR denitration reactor 3 is connected to the inlet of the hot blast stove heat exchanger 4 through an outlet flue. The outlet of the hot blast stove heat exchanger 4 is connected to the inlet of the dust collector 7 through the outlet flue via the desulfurizer powder bin 5. The clean flue gas outlet of the dust collector 7 is connected to the chimney 11 through the outlet flue via the first induced draft fan 9.

[0092] Wherein, an ammonia injection device is provided on the inlet flue, and the ammonia injection device is connected to the ammonia zone 2 through an ammonia supply pipeline;

[0093] The SCR denitration reactor is arranged in three compartments, including a denitration inlet smoke box and multiple SCR denitration reaction chambers (such as Figure 1 3 SCR denitration reaction chambers are shown in FIG), and the multiple outlets of the denitration inlet smoke box are connected to the multiple SCR denitration reaction chambers through the denitration inlet valve group 32, and the flue gas outlets of the multiple SCR denitration reaction chambers are respectively provided with a denitration outlet valve group 33;

[0094] The inlet flue and outlet flue of the hot blast furnace heat exchanger 4 are respectively provided with a heat exchanger inlet valve 41 and a heat exchanger outlet valve 42;

[0095] The hot blast stove heat exchanger 4 is also provided with a first heat regeneration flue, which connects the flue in front of the heat exchanger inlet valve 41 and the flue in front of the heat exchanger outlet valve 42, and a first heat regeneration valve 44 is provided on it;

[0096] The hot blast stove heat exchanger 4 is also provided with a second heat regeneration flue, which connects the flue after the heat exchanger inlet valve 41 and the flue after the heat exchanger outlet valve 42, and a second heat regeneration valve 45 is provided on it;

[0097] The hot blast furnace heat exchanger 4 is further provided with a heat exchanger bypass flue, which connects the flue before the heat exchanger inlet valve 41 and the flue after the heat exchanger outlet valve 42, and a heat exchanger bypass valve 43 is provided on it;

[0098] The desulfurizer powder bin 5 is connected to the outlet flue of the hot blast furnace heat exchanger 4 through an injection pipeline via an injection device, such as a conveying fan;

[0099] Wherein, a cooling device 6 is provided on the flue between the desulfurizer powder bin 5 and the dust collector 7. The cooling device 6 may be a cold air valve, a cooling water spray gun or a water spray cooling valve group;

[0100] The system further includes a second induced draft fan 10, and the clean flue gas outlet of the dust collector 7 is connected to the chimney 11 through the outlet flue in sequence via the first induced draft fan inlet valve 91, the first induced draft fan 9 and the first induced draft fan outlet valve 92;

[0101] The clean flue gas outlet of the dust collector 7 is also connected to the chimney 11 through the outlet flue in sequence via the second induced draft fan inlet valve 101, the second induced draft fan 10 and the second induced draft fan outlet valve 102;

[0102] Wherein, the dust collector 7 is arranged in chambers (such as Figure 1 8 dust collector chambers are shown in the figure), the inlet and outlet of each chamber of the dust collector 7 are respectively provided with a dust collector inlet valve and a dust collector outlet valve, and an ash conveying system is provided under the dust collector 7, which is connected to the by-product bin 8.

[0103] Example 2

[0104] This embodiment provides a blast furnace hot blast stove synchronous desulfurization and denitrification system, wherein the system includes:

[0105] The blast furnace hot blast stove synchronous desulfurization and denitrification system comprises: a blast furnace hot blast stove, an ammonia zone, an SCR denitrification reactor, a hot blast stove heat exchanger, a desulfurizer powder bin, a dust collector, a first induced draft fan and a chimney;

[0106] The flue gas outlet of the blast furnace hot blast stove and the ammonia zone are respectively connected to the flue gas inlet of the SCR denitration reactor through an inlet flue and an ammonia supply pipeline. The flue gas outlet of the SCR denitration reactor is connected to the inlet of the hot blast stove heat exchanger through an outlet flue. The outlet of the hot blast stove heat exchanger is connected to the inlet of the dust collector through the outlet flue via a desulfurizer powder bin. The clean flue gas outlet of the dust collector is connected to the chimney through the outlet flue via a first induced draft fan.

[0107] Wherein, an ammonia injection device is provided on the inlet flue, and the ammonia injection device is connected to the ammonia zone through an ammonia supply pipeline;

[0108] The SCR denitration reactor is a single-chamber structure, and its inlet and outlet are not provided with valves;

[0109] Wherein, the inlet flue and outlet flue of the hot blast furnace heat exchanger are respectively provided with a heat exchanger inlet valve and a heat exchanger outlet valve;

[0110] The hot blast stove heat exchanger is also provided with a first heat regeneration flue, which connects the flue in front of the heat exchanger inlet valve and the flue in front of the heat exchanger outlet valve, and is provided with a first heat regeneration valve;

[0111] The hot blast stove heat exchanger is also provided with a second heat regeneration flue, which connects the flue after the heat exchanger inlet valve and the flue after the heat exchanger outlet valve, and is provided with a second heat regeneration valve;

[0112] The hot blast furnace heat exchanger is further provided with a heat exchanger bypass flue, which connects the flue before the heat exchanger inlet valve and the flue after the heat exchanger outlet valve, and a heat exchanger bypass valve is provided on the flue;

[0113] Wherein, the desulfurizer powder bin is connected to the outlet flue of the hot blast furnace heat exchanger through an injection pipeline via an injection device, such as a conveying fan;

[0114] Wherein, a cooling device is provided on the flue between the desulfurizer powder bin and the dust collector, and the cooling device may be a cold air valve, a cooling water spray gun or a water spray cooling valve group;

[0115] The system further comprises a second induced draft fan, and the clean flue gas outlet of the dust collector is connected to the chimney through an outlet flue in sequence via a first induced draft fan inlet valve, a first induced draft fan and a first induced draft fan outlet valve;

[0116] The clean flue gas outlet of the dust collector is also connected to the chimney through the outlet flue in sequence via the second induced draft fan inlet valve, the second induced draft fan and the second induced draft fan outlet valve;

[0117] The dust collector is arranged in chambers, and the inlet and outlet of each chamber of the dust collector are respectively provided with a dust collector inlet valve and a dust collector outlet valve. An ash conveying system is provided under the dust collector and is connected to the by-product bin.

[0118] Example 3

[0119] This embodiment provides a blast furnace hot blast stove synchronous desulfurization and denitrification process, which is implemented using the blast furnace hot blast stove synchronous desulfurization and denitrification system provided in Example 1, wherein the process includes the following specific steps:

[0120] 2500m 3 The blast furnace is equipped with three hot blast furnaces, two for burning and one for sending. During normal production, the flue gas temperature before the hot blast furnace heat exchanger is 280℃, and the short-term high temperature can reach 360℃. The temperature after the hot blast furnace heat exchanger is 120-140℃, and the flue gas volume is 320,000Nm 3 / h, SO2≤120mg / Nm 3 , NOx≤250mg / Nm 3 .

[0121] To make SO2 in flue gas less than 30mg / Nm 3 , NOx<50mg / Nm 3 , particulate matter <5mg / Nm 3 , it is necessary to configure the hot blast furnace flue gas desulfurization and denitrification. For this, the blast furnace hot blast furnace synchronous desulfurization and denitrification system provided in Example 1 is used to treat the blast furnace hot blast furnace flue gas. The denitrification is placed before the hot blast furnace heat exchanger, and the SCR denitrification process is adopted. The desulfurization is placed after the hot blast furnace heat exchanger, and the SDS desulfurization process is adopted.

[0122] Ammonia is used as the reducing agent for denitration. Hot flue gas from the hot air furnace heat exchanger and after denitration serves as the heat source for the ammonia evaporator. After evaporation, it is diluted to a concentration of <5% by volume by a dilution fan and then sprayed into the SCR denitration reactor. Baking soda is used as the desulfurization agent for desulfurization. After being ground to 600-800 mesh in a mill, it is sprayed into the flue reactor. The denitration and desulfurization processes can be carried out according to the following specific steps:

[0123] (1) The flue gas from the blast furnace hot blast stove outlet is directly sent to the SCR denitrification reactor. In the SCR denitrification reactor, the NOx in the flue gas reacts with the denitrification reducing agent sent from the ammonia zone under the action of the SCR catalyst to complete the denitrification;

[0124] (2) The high-temperature flue gas after denitrification enters the hot air furnace heat exchanger to recover heat and obtain cooled flue gas;

[0125] (3) The cooled flue gas reacts with the desulfurizer sprayed from the desulfurizer powder bin in the outlet flue to complete the desulfurization;

[0126] (4) The flue gas after desulfurization carries a large amount of by-product powder into the dust collector and undergoes gas-solid separation to obtain clean flue gas and by-products. The clean flue gas is sucked by the induced draft fan and sent to the chimney for discharge. At the same time, the by-products separated by the dust collector are sent to the by-product bin.

[0127] In order to ensure the synchronous operation rate of desulfurization and denitrification with the blast furnace hot blast stove, the SCR denitrification reactor adopts a compartment structure, and the inlet and outlet of each compartment are respectively provided with a denitrification inlet valve group and a denitrification outlet valve group; the dust collector also adopts a compartment structure, and the inlet and outlet of each chamber are respectively provided with a dust collector inlet valve and a dust collector outlet valve, and a cold air valve is provided in the dust collector inlet flue; the induced draft fan adopts a full-load one-in-one standby configuration, and the inlet and outlet are respectively provided with an induced draft fan inlet valve and an induced draft fan outlet valve; the hot blast stove heat exchanger is provided with a heat exchanger bypass valve, a first heat regeneration valve and a second heat regeneration valve.

[0128] During normal operation, the flue gas from the blast furnace hot blast stove is mixed with ammonia from the ammonia area, and all chambers in the SCR denitrification reactor are put into use to complete denitrification; the clean flue gas obtained after treatment in the SCR denitrification reactor is cooled by the hot blast stove heat exchanger and mixed with the desulfurizer from the desulfurizer powder bin to complete desulfurization; the flue gas obtained after desulfurization is dust-removed, and particulate matter emissions meet the standards.

[0129] When the SCR catalyst needs to be replaced or the SCR catalyst unit needs to be sampled and tested (the conventional SCR catalyst used in this field can be reasonably selected and used as needed), the denitrification inlet valve group and the denitrification outlet valve group of the corresponding chamber of the SCR denitrification reactor are closed to take some chambers offline while other chambers continue to be put into use.

[0130] After the hot blast stove heat exchanger has been running for a period of time, the heat exchanger inlet valve, heat exchanger outlet valve and heat exchanger bypass valve can be closed, and the first heat regeneration valve and the second heat regeneration valve can be opened to perform heat regeneration on the hot blast stove heat exchanger. The specific operation of the heat regeneration includes:

[0131] Close the heat exchanger inlet valve, heat exchanger outlet valve and heat exchanger bypass valve, open the first heat regeneration valve and the second heat regeneration valve, so that the hot flue gas enters from the cold end of the hot blast furnace heat exchanger and is discharged from the hot end, so that the ammonium sulfate scale at the cold end is decomposed at high temperature, completing the thermal regeneration of the low-temperature end of the hot blast furnace heat exchanger.

[0132] When the desulfurization temperature is ≤130℃, the heat exchanger bypass valve can be partially opened to introduce high-temperature flue gas to increase the temperature of the flue gas after heat exchange, thereby ensuring the required temperature for desulfurization.

[0133] When the hot blast furnace heat exchanger is under maintenance, the dust collector inlet temperature may reach 300°C. At this time, the flue gas can be cooled to a reasonable range by opening the cold air valve.

[0134] In this embodiment, two induced draft fans are provided, and one is used and the other is in standby. When one induced draft fan fails, the inlet valve and outlet valve of the induced draft fan are closed for maintenance, and the other is started to ensure the availability of the system. During normal operation, the machine can also be reversed regularly.

[0135] This embodiment utilizes the synchronous desulfurization and denitrification system for the blast furnace hot blast stove provided in Example 1 to denitrify and desulfurize the blast furnace hot blast stove, thereby realizing online maintenance and inspection, and desulfurization and denitrification without stopping the operation and affecting the process production of the blast furnace hot blast stove.

[0136] Example 4

[0137] This embodiment provides a blast furnace hot blast stove synchronous desulfurization and denitrification process, which is implemented using the blast furnace hot blast stove synchronous desulfurization and denitrification system provided in Example 2, wherein the process includes the following specific steps:

[0138] 1800m3 The blast furnace is equipped with four hot blast stoves, two for burning and two for sending. During normal production, the flue gas temperature before the hot blast stove heat exchanger is 300℃, the maximum short-term temperature can reach 400℃, the temperature after the hot blast stove heat exchanger is 140-150℃, and the flue gas volume is 290000Nm 3 / h, SO2≤100mg / Nm 3 , NOx≤200mg / Nm 3 .

[0139] To make SO2<30mg / Nm 3 , NOx<50mg / Nm 3 , particulate matter <5mg / Nm 3 , it is necessary to configure the hot blast furnace flue gas desulfurization and denitrification. For this, the blast furnace hot blast furnace synchronous desulfurization and denitrification system provided in Example 2 is used to treat the blast furnace hot blast furnace flue gas. The denitrification is placed before the hot blast furnace heat exchanger, and the SCR denitrification process is adopted. The desulfurization is placed after the hot blast furnace heat exchanger, and the SDS desulfurization process is adopted.

[0140] Urea is used as a denitrification reducing agent. Urea is first prepared into a solution, then diluted, atomized with nitrogen, and sprayed directly into the SCR denitrification reactor. Baking soda is used as a desulfurization agent. After being ground to 800-1000 mesh using a domestic mill, it is sprayed into the desulfurization flue reactor. The denitrification and desulfurization processes can be carried out according to the following specific steps:

[0141] (1) The flue gas from the blast furnace hot blast stove outlet is directly sent to the SCR denitrification reactor. In the SCR denitrification reactor, the NOx in the flue gas reacts with the denitrification reducing agent sent from the ammonia zone under the action of the SCR catalyst to complete the denitrification;

[0142] (2) The high-temperature flue gas after denitrification enters the hot air furnace heat exchanger to recover heat and obtain cooled flue gas;

[0143] (3) The cooled flue gas reacts with the desulfurizer sprayed from the desulfurizer powder bin in the outlet flue to complete the desulfurization;

[0144] (4) The flue gas after desulfurization carries a large amount of by-product powder into the dust collector and undergoes gas-solid separation to obtain clean flue gas and by-products. The clean flue gas is sucked by the induced draft fan and sent to the chimney for discharge. At the same time, the by-products separated by the dust collector are sent to the by-product bin.

[0145] Among them, the SCR denitrification reactor is a single-chamber structure with no valves at its inlet and outlet; the dust collector adopts a chamber structure, and the inlet and outlet of each chamber are respectively provided with a dust collector inlet valve and a dust collector outlet valve, and a cooling water spray gun is provided in the dust collector inlet flue; two induced draft fans are used, and the two use 50% load as online standby for each other, and the inlet and outlet are respectively provided with an induced draft fan inlet valve and an induced draft fan outlet valve; the hot blast furnace heat exchanger is provided with a heat exchanger bypass valve, a first heat regeneration valve and a second heat regeneration valve.

[0146] During normal operation, urea is sprayed into the flue to evaporate and decompose into NH3. The blast furnace hot blast stove flue gas is mixed with ammonia and then enters the SCR denitrification reactor, where denitrification is completed under the catalytic reduction action of the SCR catalyst; the clean flue gas obtained by denitrification is cooled by the hot blast stove heat exchanger and then mixed with the desulfurizer from the desulfurizer powder bin to complete desulfurization; the flue gas obtained after desulfurization is dust-removed, and particulate matter emissions meet the standards.

[0147] During the intervals when the blast furnace or hot blast stove is shut down, the SCR catalyst (conventional SCR catalysts used in this field can be reasonably selected and used as needed) is replaced and the SCR catalyst unit is sampled and tested.

[0148] After the hot blast stove heat exchanger has been running for a period of time, the heat exchanger inlet valve, heat exchanger outlet valve and heat exchanger bypass valve can be closed, and the first heat regeneration valve and the second heat regeneration valve can be opened to perform heat regeneration on the hot blast stove heat exchanger. The specific operation of the heat regeneration includes:

[0149] Close the heat exchanger inlet valve, heat exchanger outlet valve and heat exchanger bypass valve, open the first heat regeneration valve and the second heat regeneration valve, so that the hot flue gas enters from the cold end of the hot blast furnace heat exchanger and is discharged from the hot end, so that the ammonium sulfate scale at the cold end is decomposed at high temperature, completing the thermal regeneration of the low-temperature end of the hot blast furnace heat exchanger.

[0150] When the desulfurization temperature is ≤130℃, the combustion temperature of the blast furnace hot blast stove can be increased to achieve flue gas temperature increase and meet the desulfurization temperature requirement. Alternatively, the heat exchanger bypass valve can be partially opened to introduce high-temperature flue gas to increase the temperature of the flue gas after heat exchange and meet the required desulfurization temperature.

[0151] When the hot blast furnace heat exchanger is under maintenance and the dust collector inlet temperature is too high, the cooling water spray gun can be activated to reduce the flue gas temperature to a reasonable range to ensure the safety of the filter bags used in the dust collector. In addition, by closing the inlet and outlet valves of the dust collector, a part of the room can be taken offline for bag replacement without affecting the hot blast furnace production.

[0152] In this embodiment, two induced draft fans are provided, and the two induced draft fans are used simultaneously and serve as backup for each other. When one induced draft fan fails, the inlet valve and outlet valve of the failed induced draft fan can be closed to carry out maintenance, while reducing the load of the blast furnace hot blast stove to ensure that the blast furnace does not stop production.

[0153] To sum up, the synchronous desulfurization and denitrification system and process for the blast furnace hot blast stove provided by the embodiment of the present invention can perform equipment inspection and maintenance online through the SCR denitrification reactor compartment, the dust collector compartment and the provision of a spare induced draft fan, thereby achieving 100% synchronization of desulfurization and denitrification with hot blast stove production, and desulfurization and denitrification no longer affect the normal production of the hot blast stove.

[0154] In the system provided by the embodiment of the present invention, the hot blast furnace heat exchanger is provided with a thermal regeneration valve group, which can greatly reduce the adverse effects of low-temperature adhesion scaling of the hot blast furnace heat exchanger, such as ammonium sulfate scaling, on the low-temperature end of the hot blast furnace heat exchanger, such as blockage, increased resistance loss, and reduced heat exchange efficiency, thereby improving the efficiency of the heat exchanger and extending the life of the equipment; at the same time, during thermal regeneration, the flue gas temperature exiting the hot blast furnace heat exchanger does not change significantly, and the dust collector bag will not be damaged due to high temperature.

[0155] In the system provided in the embodiment of the present invention, the hot blast furnace heat exchanger is also provided with a heat exchanger bypass flue and a heat exchanger bypass valve. Desulfurization and temperature increase can be achieved by controlling the heat exchanger bypass valve, thereby ensuring the desulfurization temperature requirement; in addition, desulfurization and temperature increase can also be achieved by increasing the combustion temperature of the hot blast furnace without the need for additional heating devices.

[0156] Compared to traditional denitrification systems, in the system provided by the embodiment of the present invention, the SCR denitrification reactor is located before the hot blast furnace heat exchanger, and there is no need to set up a heating device (such as a heating furnace and GGH heat exchanger, etc.), which reduces equipment investment and system resistance, thereby saving electricity consumption; because there is no heating device, there is no need to burn blast furnace gas for heating, which correspondingly reduces the amount of equipment maintenance and there is no consumption of energy media such as gas; and desulfurization is carried out after heat exchange, and there is no need to set up a heating device. In short, the system and process provided by the embodiment of the present invention have low investment and operating costs, simple operation and maintenance, and eliminate the adverse effects on hot blast furnace production.

[0157] Therefore, the synchronous desulfurization and denitrification system and process for blast furnace hot blast stoves provided by the embodiments of the present invention removes SO2 and NOx from the flue gas generated by the blast furnace hot blast stove. While achieving blast furnace hot blast stove flue gas purification, it can also achieve 100% synchronous operation of the desulfurization and denitrification process and the main process of the hot blast stove. The desulfurization and denitrification equipment can be maintained online, solving the problem of blast furnace production being affected by the configuration of desulfurization and denitrification equipment, and also reducing the investment and operating costs of desulfurization and denitrification. On the basis of achieving flue gas desulfurization and denitrification emission standards, the operation and maintenance of the entire system can be made without affecting the operation of the blast furnace hot blast stove, and the risk of blockage of the blast furnace hot blast stove heat exchanger by ammonium sulfate and the like can be solved.

[0158] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, substitutions of equivalent components, or equivalent changes and modifications made within the scope of patent protection, should still fall within the scope of this patent. Furthermore, the technical features of this invention may be freely combined with one another, with other technical inventions, and with other technical inventions.

Claims

1. A blast furnace hot blast stove synchronous desulfurization and denitrification system, characterized in that: The blast furnace hot blast stove synchronous desulfurization and denitrification system comprises: a blast furnace hot blast stove, an ammonia zone, an SCR denitrification reactor, a hot blast stove heat exchanger, a desulfurizer powder bin, a dust collector, a first induced draft fan and a chimney; The flue gas outlet of the blast furnace hot blast stove and the ammonia zone are respectively connected to the flue gas inlet of the SCR denitration reactor through an inlet flue and an ammonia supply pipeline. The flue gas outlet of the SCR denitration reactor is connected to the inlet of the hot blast stove heat exchanger through an outlet flue. The outlet of the hot blast stove heat exchanger is connected to the inlet of the dust collector through the outlet flue via a desulfurizer powder bin. The clean flue gas outlet of the dust collector is connected to the chimney through the outlet flue via a first induced draft fan. The SCR denitration reactor is arranged in compartments, including a denitration inlet smoke box and multiple SCR denitration reaction chambers, the multiple outlets of the denitration inlet smoke box are respectively connected to the multiple SCR denitration reaction chambers through denitration inlet valve groups, and the flue gas outlets of the multiple SCR denitration reaction chambers are respectively provided with denitration outlet valve groups; or the SCR denitration reactor is a single-compartment structure, and its inlet and outlet are not provided with valves; The inlet flue and outlet flue of the hot blast stove heat exchanger are respectively provided with a heat exchanger inlet valve and a heat exchanger outlet valve; The hot blast stove heat exchanger is also provided with a first heat regeneration flue, which connects the flue in front of the heat exchanger inlet valve and the flue in front of the heat exchanger outlet valve, and is provided with a first heat regeneration valve; The hot blast stove heat exchanger is further provided with a second heat regeneration flue, which connects the flue behind the heat exchanger inlet valve and the flue behind the heat exchanger outlet valve, and is provided with a second heat regeneration valve.

2. The blast furnace hot blast stove synchronous desulfurization and denitrification system according to claim 1, characterized in that: An ammonia injection device is provided on the inlet flue, and the ammonia injection device is connected to the ammonia zone through an ammonia supply pipeline.

3. The blast furnace hot blast stove synchronous desulfurization and denitrification system according to claim 1, characterized in that: The hot blast stove heat exchanger is further provided with a heat exchanger bypass flue, which connects the flue before the heat exchanger inlet valve and the flue after the heat exchanger outlet valve, and a heat exchanger bypass valve is provided on the flue.

4. The blast furnace hot blast stove synchronous desulfurization and denitrification system according to claim 1 or 2, characterized in that: The desulfurizer powder bin is connected to the outlet flue of the hot blast stove heat exchanger via an injection pipeline and an injection device.

5. The blast furnace hot blast stove synchronous desulfurization and denitrification system according to claim 4, characterized in that: A flue-type reactor is provided on the outlet flue of the hot blast stove heat exchanger, and the desulfurizer powder bin is connected to the flue-type reactor via an injection pipeline and an injection device.

6. The blast furnace hot blast stove synchronous desulfurization and denitrification system according to claim 1 or 2, characterized in that: A cooling device is provided on the flue between the desulfurizer powder bin and the dust collector.

7. The blast furnace hot blast stove synchronous desulfurization and denitrification system according to claim 1 or 2, characterized in that: The system further comprises a second induced draft fan, wherein the clean flue gas outlet of the dust collector is connected to the chimney via an outlet flue in sequence via a first induced draft fan inlet valve, a first induced draft fan and a first induced draft fan outlet valve; The clean flue gas outlet of the dust collector is also connected to the chimney through the outlet flue in sequence via the second induced draft fan inlet valve, the second induced draft fan and the second induced draft fan outlet valve.

8. The blast furnace hot blast stove synchronous desulfurization and denitrification system according to claim 1 or 2, characterized in that: The dust collector is arranged in chambers, and the inlet and outlet of each chamber of the dust collector are respectively provided with a dust collector inlet valve and a dust collector outlet valve. An ash conveying system is provided under the dust collector and is connected to the by-product bin.

9. A blast furnace hot blast stove synchronous desulfurization and denitrification process, characterized in that: The blast furnace hot blast stove synchronous desulfurization and denitrification process is realized by using the blast furnace hot blast stove synchronous desulfurization and denitrification system according to any one of claims 1 to 8, comprising: (1) The flue gas from the blast furnace hot blast stove outlet is directly sent to the SCR denitrification reactor. In the SCR denitrification reactor, the NOx in the flue gas reacts with the denitrification reducing agent sent from the ammonia zone under the action of the SCR catalyst to complete the denitrification; (2) The high-temperature flue gas after denitrification enters the hot air furnace heat exchanger to recover heat and obtain cooled flue gas; (3) The cooled flue gas reacts with the desulfurizer sprayed from the desulfurizer powder bin in the outlet flue to complete desulfurization; (4) The flue gas after desulfurization enters the dust collector and undergoes gas-solid separation to obtain clean flue gas and by-products. The clean flue gas is sucked by the induced draft fan and sent to the chimney for discharge.

10. The process for simultaneous desulfurization and denitrification of a blast furnace hot blast stove according to claim 9, characterized in that: When the cold end of the hot blast stove heat exchanger is scaled due to low temperature, the process further includes thermally regenerating the hot blast stove heat exchanger, and the thermal regeneration includes: Close the heat exchanger inlet valve, heat exchanger outlet valve and heat exchanger bypass valve, open the first heat regeneration valve and the second heat regeneration valve, so that the hot flue gas enters from the cold end of the hot blast stove heat exchanger and is discharged from the hot end, so that the scale on the cold end is decomposed at high temperature, completing the regeneration of the hot blast stove heat exchanger.

11. The process for simultaneous desulfurization and denitrification of a blast furnace hot blast stove according to claim 9 or 10, characterized in that: When the temperature of the desulfurization process is ≤130°C, the process further comprises: Partially open the bypass valve of the heat exchanger to mix the high-temperature flue gas with the low-temperature flue gas after passing through the hot blast furnace heat exchanger, so that the system temperature reaches the temperature required for desulfurization.

12. The process for simultaneous desulfurization and denitrification of a blast furnace hot blast stove according to claim 9 or 10, characterized in that: When the inlet flue gas temperature of the dust collector is higher than the temperature resistance of the dust collector filter bag, the cooling device is started to cool the flue gas.

13. The process for simultaneous desulfurization and denitrification of a blast furnace hot blast stove according to claim 9 or 10, characterized in that: The temperature range of the flue gas at the outlet of the hot blast stove is 230-360°C, and the temperature range of the flue gas after the hot blast stove heat exchanger is 110-160°C.

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