High-temperature flue gas desulfurization treatment system for steel rolling hot rolling heating furnace

Abstract

The invention discloses a steel rolling hot rolling heating furnace high-temperature flue gas desulfurization treatment system, and relates to the technical field of waste gas treatment. The high-temperature flue gas desulfurization treatment system for the steel rolling hot-rolling heating furnace is specifically operated as follows: during working, flue gas of the steel rolling hot-rolling heating furnace passes through the flue gas collecting cover and is led out, a calcium-based desulfurizer is sprayed into the inlet flue, and the desulfurizer is in full contact with the original flue gas. Compared with the prior art, the high-temperature flue gas desulfurization treatment system for the steel rolling hot rolling heating furnace has the advantages that calcium-based dry desulfurization and ceramic fiber filter tube dust removal are adopted in the treatment process, high-temperature flue gas can be tolerated while high-efficiency desulfurization and dust removal are realized, a forced flue gas cooling mode is not needed, and meanwhile, further waste heat recycling of subsequent flue gas is not influenced; the temperature drop of the whole system can be controlled within 20 DEG C, ultralow emission of desulfurization and dust removal is achieved, denitration can be further achieved under the conditions that a denitration filter pipe is adopted and an ammonia spraying system is additionally arranged, and the pollutant control target with higher requirements is met.

Description

Technical Field

[0001] The invention relates to the technical field of waste gas treatment, and in particular to a high-temperature flue gas desulfurization treatment system for a steel rolling hot rolling heating furnace. Background Art

[0002] The hot rolling production line of steel enterprises is generally composed of a heating furnace, a main rolling line, a grinding roller room, a finishing line, etc. The heating furnace generally uses coal gas as fuel to heat treat the steel billet for subsequent rolling. The heating furnace system includes burners, combustion air ducts, gas ducts, etc. The fuel-gas of the heating furnace will produce SO2, NOX, and dust during combustion. In April 2019, the Ministry of Ecology and Environment and five other ministries and commissions jointly issued the "Opinions on Promoting the Implementation of Ultra-low Emissions in the Steel Industry", which requires the emission of pollutants from heating furnaces: NOx emission concentration ≤ 200mg / Nm3, SO2 emission concentration ≤ 50mg / Nm3, and particulate matter emission concentration ≤ 10mg / Nm3. Therefore, by adding flue gas desulfurization equipment, pollutant emissions can be greatly reduced, air quality can be improved, and it is of great significance to building a beautiful environment with blue sky and green water and promoting sustainable social and economic development.

[0003] Flue gas desulfurization technologies mainly include dry desulfurization, semi-dry desulfurization and wet desulfurization. The efficiency of dry desulfurization is relatively low, the desulfurization efficiency of semi-dry desulfurization is medium, and the efficiency of wet desulfurization is the highest. Dry desulfurization mainly includes processes such as "SDS sodium method" and "calcium-based dry method", which are widely used in flue gas desulfurization at low SO2 concentrations. The flue gas from the heating furnace belongs to the flue gas with low SO2 concentration. Therefore, the above-mentioned process used in recent years is the main choice for the purification of flue gas from the heating furnace. However, since the waste heat recovery of the flue gas from the relevant heating furnace is not implemented, the flue gas emission temperature is generally higher than 350°C, and the above-mentioned desulfurization process needs to be cooled first. The present invention proposes a desulfurization and dust removal treatment system process for the flue gas from high-temperature heating furnaces, namely, calcium-based dry desulfurization + ceramic filter tube dust collector technology.

[0004] A total of 66 patents were retrieved using the keyword "heating furnace flue gas desulfurization", of which 5 patents are highly relevant to this patent; as shown below, however, none of these 5 patents can replace the technical characteristics of this patent.

[0005] The invention of publication number: CN117919910A "A conventional steel rolling heating furnace flue gas desulfurization system and device" discloses a conventional steel rolling heating furnace flue gas desulfurization system and device, including an inlet main pipe, a waste heat boiler, an economizer, an outlet main pipe and a desulfurization tower, one end of the inlet main pipe is connected to the underground flue in front of the chimney entrance at the air intake point, the waste heat boiler and the economizer are both installed in the underground flue, the heating furnace, the waste heat boiler, the economizer and the air intake point are arranged in sequence on the flue gas path, one end of the outlet main pipe is connected to the underground flue in front of the chimney entrance at the air return point, a sealed partition wall is installed in the underground flue between the air intake point and the air return point, a booster fan is installed on the outlet main pipe, and the desulfurization tower includes a chamber structure with two left and right flue gas channels.

[0006] The utility model with publication number: CN221123046U "A flue gas treatment system for a heat storage steel rolling heating furnace" belongs to the technical field of flue gas treatment of heating furnaces, and particularly relates to a flue gas treatment system for a heat storage steel rolling heating furnace. The utility model includes a heat storage steel rolling heating furnace, the outlet of which is connected to a coal smoke flue and an air smoke flue, the coal smoke flue is sequentially connected to a coal smoke desulfurization reactor, a coal smoke dust collector, a coal smoke denitrification reactor, a coal smoke induced draft fan and a coal smoke chimney, and the air smoke flue is sequentially connected to an air smoke desulfurization reactor, an air smoke dust collector, an air smoke denitrification reactor, an air smoke induced draft fan and an air smoke chimney. The utility model provides a flue gas treatment system for a heat storage steel rolling heating furnace that has ultra-low emissions of flue gas pollutants, fully utilizes the heat of the flue gas from the supplementary hot blast furnace, and ensures safety.

[0007] The invention disclosure of publication number: CN116966738A "A flue gas desulfurization and dust removal device and process for a steel rolling heating furnace" proposes a flue gas desulfurization and dust removal device and process for a steel rolling heating furnace, including a treatment tower, having a liquid inlet and an exhaust port, an impeller, rotatably arranged at the bottom of the treatment tower, a drainage tube, rotatably arranged on the treatment tower, located above the impeller, the drainage tube having a drainage port, a drainage area formed between the outer wall of the drainage tube and the inner wall of the treatment tower, a treatment area formed between the inner wall of the drainage tube and the inner wall of the treatment tower, the treatment area connected to the drainage area through the drainage port, the liquid inlet and the exhaust port are both connected to the treatment area, and the impeller is located in the treatment area. The solution solves the problem in the prior art that the flue gas is mixed with the descending alkali solution spray during the rising process, resulting in insufficient mixing, and the cost of multiple treatments is high.

[0008] The utility model of publication number: CN220110764U "A thermal storage type steel rolling heating furnace flue gas desulfurization and denitrification device" discloses a thermal storage type steel rolling heating furnace flue gas desulfurization and denitrification device, including a smoke exhaust pipe, a denitrification box and a desulfurization box, an ozone purification box is arranged between the denitrification box and the smoke exhaust pipe, an ozone distributor is arranged in the ozone purification box, a driving mechanism rotatably connected to the ozone distributor is arranged on the outer side of one end of the ozone purification box, a gas distribution plate, a spray pipe and a drying layer are arranged in sequence inside the denitrification box from top to bottom, a water inlet pipe is arranged on the spray pipe, the desulfurization box is divided into an air intake chamber and a desulfurization chamber by a horizontal partition, an air guide pipe connected to the air intake chamber is arranged on the top of the denitrification box, and a desulfurization purification component is arranged inside the desulfurization chamber. The structure of the device is compact, which can not only effectively improve the efficiency of denitration and denitrification, but also effectively reduce the cost of operation.

[0009] Publication No.: CN218784704U "An environmentally friendly heating furnace flue gas desulfurization and denitrification dust removal system" discloses an environmentally friendly heating furnace flue gas desulfurization and denitrification dust removal system, which relates to the desulfurization and denitrification technical field, including a spray tower and a lime water tank, the top of the spray tower is provided with a flue gas duct, one end of the flue gas duct extends to the inside of the lime water tank and a check elbow is installed, the beneficial effect of the utility model is: the flue gas in the spray tower can be sprayed and desulfurized and denitrified to remove the flue gas. The smoke, sulfur and nitrogen in the air are roughly filtered, and then the roughly filtered smoke is discharged into the lime water tank through the flue gas duct through the check elbow. The desulfurization and denitrification time of the smoke in the lime water tank can be extended by the guide plate, and the dust that has not been cleaned up in the smoke can also be filtered, thereby improving the dust removal effect. At the same time, the aerator inside the lime water tank makes the lime water inside it blow and churn, which can effectively mix the smoke and the lime water inside the lime water tank, thereby effectively carrying out desulfurization and denitrification treatment. Summary of the invention

[0010] 1. Technical issues to be solved

[0011] In view of the deficiencies in the prior art, the present invention provides a high-temperature flue gas desulfurization treatment system for a steel rolling hot rolling heating furnace, which solves the problems existing in the prior art.

[0012] (II) Technical solution

[0013] To achieve the above objectives, the present invention is implemented through the following technical solutions: a high-temperature flue gas desulfurization treatment system for hot rolling heating furnaces, the specific operation is as follows:

[0014] During operation, the flue gas from the hot rolling heating furnace is passed through the flue gas collection hood. After the flue gas is led out, a calcium-based desulfurizer is sprayed into the inlet flue. The desulfurizer is fully in contact with the original flue gas and quickly completes physical and chemical reactions to achieve the purpose of removing SO2 and other acidic media. It then enters the dust ceramic fiber filter tube dust removal device through the connecting flue. Dust with larger particle size settles under the action of gravity, and dust with smaller particle size is deposited on the surface of the filter material to form a dust cake layer. Secondary desulfurization is carried out on the dust cake layer on the surface of the ceramic tube, and the clean flue gas is sent into the chimney for discharge through the induced draft fan.

[0015] Preferably, the slaked lime powder required for desulfurization is purchased from outside and transported to the desulfurizer storage area, and the slaked lime powder transported by tank trucks is directly fed into the slaked lime storage. It is characterized in that a closed tank truck is used and pneumatic conveying is utilized. The ash storage bin can store a quantity not less than 30 days. A single bag dust collector is provided on the top of the bin, and the fan outlet of the dust collector on the top of the bin is connected to the flue before the filter tube dust collector to reduce the emission points of exhaust gas.

[0016] Preferably, the slaked lime powder is stored in a slaked lime bin, transported to the flue gas inlet through a weighing silo, and reacts with the acidic gas. It is characterized in that an air fluidization device is provided at the bottom of the powder storage bin to prevent bridging of the slaked lime powder, and a star-shaped ash discharge valve adopts frequency conversion control to adjust the dosage of the desulfurizer.

[0017] Preferably, the heating furnace is equipped with an online / offline dust cleaning filter tube dust collector, which is an external filtering medium and low pressure pulse filter tube dust collector, and adopts an online pulse spray cleaning method. It includes a filter tube dust collector, a spray cleaning system, an offline system, etc. The filter tube dust collector includes a structural support, a platform steel ladder, a bottom beam and a ceramic filter tube module, etc. The ceramic filter tube module includes an upper box, a middle box, an ash hopper, a flower plate, a sliding device, a cover plate, an air distribution plate, an air regulating valve, a spray device and a ceramic filter tube.

[0018] Preferably, the pulse cleaning system includes a compressed air bag, a blowpipe, a pulse valve, a piping system, and a cleaning control system. Each unit module is equipped with an air bag, and each air bag is equipped with necessary auxiliary equipment, including pipelines, accessories, shut-off valves, and control equipment. It is characterized in that the cleaning system can realize online cleaning, and the cleaning force and cleaning air volume can meet the cleaning requirements under various operating conditions. Each chamber is equipped with a control and monitoring system, and the main control functions include Δp pressure difference control, timing control, forced cleaning function, and single valve cleaning function.

[0019] Preferably, a waste ash conveying system is provided, which is composed of an ash conveying fan, an ash conveying pipeline, an ash discharge valve, an acceleration chamber, a buffer bin, a waste ash bin, and a dust collector on the top of the ash bin. The waste ash is characterized in that: the waste ash comes from the external ash discharged from the filter tube dust collector, and the external ash is conveyed to the buffer bin by the ash discharge valve and then enters the acceleration chamber from the buffer bin, and then is conveyed to the ash bin by the fluidized air generated by the ash conveying fan. The ash conveying system is provided with an anti-blocking and unblocking device, and the conveying capacity is not less than 200% of the total conveying capacity of the system.

[0020] Preferably, the smoke and air duct system is composed of an induced draft fan, an electric damper door, a smoke and air duct, etc. The induced draft fan is arranged at the end of the smoke treatment to keep the entire system at a negative pressure. The induced draft fan is used to suck the smoke emitted by the heating furnace and to overcome the resistance of the smoke duct and the ceramic filter tube dust collector to discharge the smoke into the chimney. The induced draft fan is equipped with a frequency conversion control device to automatically operate the induced draft fan according to the negative pressure signal of the heating furnace.

[0021] (III) Beneficial effects

[0022] The present invention provides a high-temperature flue gas desulfurization treatment system for a steel rolling hot rolling heating furnace. It has the following beneficial effects:

[0023] Compared with the existing technology, the high-temperature flue gas desulfurization treatment system of the steel rolling hot rolling heating furnace adopts calcium-based dry desulfurization + ceramic fiber filter tube dust removal. While achieving efficient desulfurization and dust removal, it can withstand high-temperature flue gas and does not require forced cooling of the flue gas. At the same time, it does not affect the further waste heat recovery of the subsequent flue gas. The calcium-based dry desulfurization is arranged in the high-temperature section of the flue gas. The desulfurization efficiency of the desulfurizer slaked lime increases with the increase of temperature above 200°C. The desulfurization efficiency is highest at 350°C. The high-temperature desulfurization efficiency is as high as more than 95%, and the dust removal efficiency is as high as more than 99%. The temperature drop of the entire system can be controlled within 20°C. It not only achieves ultra-low emissions of desulfurization and dust removal, but also can further achieve denitrification by using denitrification filter tubes and adding an ammonia injection system to meet higher requirements for pollutant control targets.

[0024] The method has simple process, high treatment efficiency, green and environmentally friendly treatment process, and no secondary pollution.

[0025] This method can not only effectively treat sulfur dioxide and particulate matter in the flue gas of hot rolling heating furnace, but also achieve ultra-low emission of pollutants, that is, the concentration of SO2 and particulate matter in the flue gas can reach 50mg / Nm 3 、10mg / Nm 3 , meet the requirements of national environmental protection policies; and on the basis of further adopting filter tube catalysts, realize multi-gas denitrification and meet higher requirements for pollutant control;

[0026] The desulfurization and dust removal process is suitable for the treatment of high-temperature flue gas (above 300°C) from hot rolling heating furnaces. The system temperature is reduced and does not affect the subsequent recovery of waste heat from the flue gas. It has significant environmental and social benefits and can be further promoted and applied. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the process flow of calcium-based desulfurization + ceramic fiber filter tube dust removal of the present invention;

[0028] Figure 2 This is a desulfurizing agent consumption table of an embodiment of the present invention;

[0029] Figure 3 This is a table of main body parameters of the filter tube dust collector according to an embodiment of the present invention;

[0030] Figure 4 This is a table of system resistance and fan selection according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] See also Figure 1-4 The present invention provides a technical solution: a high-temperature flue gas desulfurization treatment system for a steel rolling hot rolling heating furnace, the specific operation is as follows:

[0033] During operation, the flue gas from the hot rolling heating furnace is passed through the flue gas collection hood. After the flue gas is led out, a calcium-based desulfurizer is sprayed into the inlet flue. The desulfurizer is fully in contact with the original flue gas and quickly completes physical and chemical reactions to achieve the purpose of removing SO2 and other acidic media. It then enters the dust ceramic fiber filter tube dust removal device through the connecting flue. Dust with larger particle size settles under the action of gravity, and dust with smaller particle size is deposited on the surface of the filter material to form a dust cake layer. Secondary desulfurization is carried out on the dust cake layer on the surface of the ceramic tube, and the clean flue gas is sent into the chimney for discharge through the induced draft fan.

[0034] The slaked lime powder required for desulfurization is purchased from outside and transported to the desulfurizer storage area. The slaked lime powder transported by tank trucks is directly fed into the slaked lime storage. It is characterized by the use of closed tank trucks and pneumatic conveying. The ash storage bin can store a quantity of not less than 30 days. A single bag dust collector is installed on the top of the bin. The fan outlet of the dust collector on the top of the bin is connected to the flue before the filter tube dust collector to reduce the emission points of exhaust gas.

[0035] The slaked lime powder is stored in the slaked lime silo and transported to the flue gas inlet through a small weighing silo to react with the acid gas. It is characterized by: an air fluidization device is provided at the bottom of the powder storage silo to prevent the slaked lime powder from bridging; the star-shaped ash discharge valve adopts frequency conversion control to adjust the dosage of the desulfurizer.

[0036] The heating furnace is equipped with an online / offline dust cleaning filter tube dust collector. The dust collector type is an external filtering medium and low pressure pulse filter tube dust collector, which adopts online pulse spray cleaning method. It includes filter tube dust collector, spray cleaning system, offline system, etc. The filter tube dust collector includes structural support, platform steel ladder, bottom beam and ceramic filter tube module, among which the ceramic filter tube module includes upper box, middle box, ash hopper, flower plate, sliding device, cover plate, air distribution plate, air regulating valve, spray device and ceramic filter tube.

[0037] The pulse cleaning system includes a compressed air bag, a blowpipe, a pulse valve, a piping system, and a cleaning control system. Each unit module is equipped with an air bag, and each air bag is equipped with necessary auxiliary equipment, including pipelines, accessories, shut-off valves, and control equipment. It is characterized by: the cleaning system can realize online cleaning, and the cleaning force and cleaning air volume can meet the cleaning requirements under various operating conditions. Each room is equipped with a control and monitoring system, and the main control functions include Δp pressure difference control, timing control, forced cleaning function, and single valve cleaning function.

[0038] A waste ash conveying system is set up, which consists of an ash conveying fan, ash conveying pipeline, ash unloading valve, acceleration chamber, buffer bin, waste ash storage, ash storage bin top dust collector, etc., and is characterized in that the waste ash comes from the external ash discharged from the filter tube dust collector, the external ash is conveyed to the buffer bin by the ash unloading valve and then enters the acceleration chamber from the buffer bin, and is then conveyed to the ash storage by the fluidizing air generated by the ash conveying fan. The ash conveying system is provided with an anti-blocking and unblocking device, and the conveying capacity is not less than 200% of the total system conveying volume.

[0039] The smoke and air duct system consists of an induced draft fan, electric damper door, smoke and air duct, etc. The induced draft fan is arranged at the end of the smoke treatment to keep the whole system under negative pressure. The induced draft fan is used to suck the smoke emitted by the heating furnace and discharge the smoke into the chimney by overcoming the resistance of the smoke duct and ceramic filter tube dust collector. The induced draft fan is equipped with a frequency conversion control device to realize automatic operation of the induced draft fan according to the negative pressure signal of the heating furnace.

[0040] Example:

[0041] Take the flue gas desulfurization treatment of the heating furnace of a certain steel rolling 2250 hot-rolled slab production line as an example: there are three hot-rolled heating furnaces, the original flue gas volume of a single heating furnace is 198000Nm3 / h, the flue gas temperature is about 420℃, the inlet flue gas SO2 concentration is about 100mg / m3, and the inlet particulate matter concentration is 15mg / m3.

[0042] The technical process of calcium-based dry desulfurization + ceramic filter tube dust removal is as follows: the hot rolling 2250 production line opens a tee (before the gate) on the flue after the air preheater, and after the flue gas is drawn out, the calcium-based desulfurizer is sprayed into the new inlet flue. The desulfurizer is fully in contact with the original flue gas, and the physical and chemical reactions are quickly completed to achieve the purpose of removing SO2 and other acidic media. After that, it enters the dust ceramic fiber filter tube dust removal device through the connected flue. The dust with larger particle size settles under the action of gravity, and the dust with smaller particle size is deposited on the surface of the filter material to form a dust cake layer, and secondary desulfurization is carried out on the dust cake layer on the surface of the ceramic tube. The clean flue gas without dust and sulfur in the 2250 heating furnace is discharged through the original chimney after the induced draft fan leads the purified flue gas to the gate. The specific description is as follows:

[0043] 1) The slaked lime powder required for desulfurization is purchased from outside and transported to the absorbent storage area of ​​the ceramic filter tube dust collector desulfurization island. The slaked lime powder transported by tank trucks is directly fed into the slaked lime storage and transported to the inlet flue through a weighing small bin to react with the acid gas. An air fluidization device is installed at the bottom of the powder storage bin to prevent bridging of slaked lime powder; a small bag dust collector is installed on the top, and the fan outlet of the bin top dust collector is connected to the flue before the filter tube dust collector to reduce the emission point of exhaust gas. The star-shaped ash discharge valve adopts frequency conversion control to adjust the amount of desulfurizer. According to the fuel information and desulfurization process, the desulfurizer consumption can be seen in Figure 2 The hot rolling 2250 production line is equipped with a slaked lime storage silo.

[0044] in:

[0045] ① Volume of slaked lime storage silo: 60m 3 Material: Carbon Steel

[0046] ② Air volume of powder delivery fan: 15m 3 / min pressure: 39.9KPa

[0047] ③ Acceleration chamber delivery capacity: 0-0.3t / h

[0048] ④Slaked lime silo top dust collector Filtration area: 36㎡ Type: Pulse bag dust collector

[0049] ⑤ Fluidizing fan air volume: 15m 3 / minPressure: 58.8KPa

[0050] 2) Filter tube dust removal. The heating furnace is equipped with online / offline dust cleaning filter tube dust collector, including filter tube dust collector, spray cleaning system, offline system, etc. The pulse cleaning system includes compressed air bag, spray pipe, pulse valve, pipeline system, and cleaning control system. Each unit module is equipped with an air bag, and each air bag is equipped with necessary auxiliary equipment, including pipelines, accessories, shut-off valves, and control equipment. The cleaning system can realize online cleaning, and the cleaning force and cleaning air volume can meet the cleaning under various operating conditions. The cleaning system is reasonably designed and can complete the cleaning work as required. The electromagnetic pulse valve is flexible and reliable; each room is equipped with a control and monitoring system, and the main control functions include Δp pressure difference control, timing control, forced cleaning function, and single valve cleaning function. The filter tube dust collector includes a structural support, a platform steel ladder, a bottom beam, and a ceramic filter tube module, among which the ceramic filter tube module includes an upper box, a middle box, an ash hopper, a flower plate, a sliding device, a cover plate, an air distribution plate, an air regulating valve, a spray device, and a ceramic filter tube. The dust collector is an external filtering medium and low pressure pulse filter tube dust collector, which adopts online pulse jet cleaning method. Each of the three heating furnaces of the hot rolling 2250 production line is equipped with a 10-chamber filter tube dust collector. The main parameters of the filter tube dust collector are as follows Figure 3 As shown;

[0051] 3) Waste ash conveying system. The waste ash conveying system consists of ash conveying fan, ash conveying pipeline, ash discharge valve, acceleration chamber, buffer bin, waste ash storage, ash storage top dust collector, etc. The waste ash of this project comes from the external ash discharged from the filter tube dust collector. The external ash is conveyed to the buffer bin by the ash discharge valve and then enters the acceleration chamber from the buffer bin, and then is conveyed to the ash storage by the fluidized air generated by the ash conveying fan. The ash conveying system is equipped with an anti-blocking and unblocking device, and the conveying capacity is not less than 200% of the total conveying capacity of the system. The main equipment parameters of this system are as follows:

[0052] ① Volume of waste ash storage: 90m 3 Material: Carbon Steel

[0053] ② Ash conveying fan air volume: 20m 3 / minPressure: 68.8KPa

[0054] ③ Ash silo top dust collector Filtration area: 108㎡ Type: Pulse bag dust collector

[0055] ④ Ash discharge valve temperature resistance: up to 350℃ Delivery capacity: 3t / h

[0056] ⑤ Dry ash bulk machine processing capacity: 0-60t / h

[0057] Smoke and air duct system. The smoke and air duct system consists of induced draft fan, electric damper door, smoke and air duct, etc. The induced draft fan is arranged at the end of the smoke treatment to keep the whole system under negative pressure. An induced draft fan is set to suck the smoke emitted by the heating furnace and discharge the smoke into the chimney by overcoming the resistance of the smoke duct and ceramic filter tube dust collector. The induced draft fan is equipped with a frequency conversion control device to realize automatic operation of the induced draft fan according to the negative pressure signal of the heating furnace. Figure 4 As shown;

[0058] 5) Other public utilities. Mainly involving power supply, compressed air, CEMS and other instruments, etc.

[0059] After the flue gas purification system of the 2250 hot rolling heating furnace was transformed using this process technology, the three heating furnaces of the 2250 hot rolling production line can achieve a smoke removal capacity of 8t / a and a SO2 removal capacity of 65t / a, based on an annual operating time of 8,000 hours. At the same time, the above pollutant emissions meet the ultra-low emission limit.

[0060] It meets the latest national pollutant emission limit requirements, helps improve the local environment, and has good environmental and social benefits.

[0061] In summary, compared with the existing technology, the high-temperature flue gas desulfurization treatment system of the steel rolling hot rolling heating furnace adopts calcium-based dry desulfurization + ceramic fiber filter tube dust removal. While achieving efficient desulfurization and dust removal, it can withstand high-temperature flue gas and does not require forced cooling of the flue gas. At the same time, it does not affect the further waste heat recovery of the subsequent flue gas. The calcium-based dry desulfurization is arranged in the high-temperature section of the flue gas. The desulfurization efficiency of the desulfurizer slaked lime increases with the increase of temperature above 200°C. The desulfurization efficiency is highest at 350°C. The high-temperature desulfurization efficiency is as high as more than 95%, and the dust removal efficiency is as high as more than 99%. The temperature drop of the entire system can be controlled within 20°C, which not only achieves ultra-low emissions of desulfurization and dust removal, but also can further achieve denitrification by using denitrification filter tubes and adding an ammonia injection system to meet higher requirements for pollutant control targets;

[0062] The method has simple process, high treatment efficiency, green and environmentally friendly treatment process, and no secondary pollution.

[0063] This method can not only effectively treat sulfur dioxide and particulate matter in the flue gas of hot rolling heating furnace, but also achieve ultra-low emission of pollutants, that is, the concentration of SO2 and particulate matter in the flue gas can reach 50mg / Nm 3 、10mg / Nm 3 , meet the requirements of national environmental protection policies; and on the basis of further adopting filter tube catalysts, realize multi-gas denitrification and meet higher requirements for pollutant control;

[0064] The desulfurization and dust removal process is suitable for the treatment of high-temperature flue gas (above 300°C) from hot rolling heating furnaces. The system temperature is reduced and does not affect the subsequent recovery of waste heat from the flue gas. It has significant environmental and social benefits and can be further promoted and applied.

[0065] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0066] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-temperature flue gas desulfurization treatment system for hot rolling heating furnace, characterized in that: The specific operations are as follows: During operation, the flue gas from the hot rolling heating furnace is passed through the flue gas collection hood. After the flue gas is led out, a calcium-based desulfurizer is sprayed into the inlet flue. The desulfurizer is fully in contact with the original flue gas and quickly completes physical and chemical reactions to achieve the purpose of removing SO2 and other acidic media. It then enters the dust ceramic fiber filter tube dust removal device through the connecting flue. Dust with larger particle size settles under the action of gravity, and dust with smaller particle size is deposited on the surface of the filter material to form a dust cake layer. Secondary desulfurization is carried out on the dust cake layer on the surface of the ceramic tube, and the clean flue gas is sent into the chimney for discharge through the induced draft fan.

2. A high-temperature flue gas desulfurization treatment system for hot rolling heating furnace of steel rolling according to claim 1, characterized in that: The slaked lime powder required for desulfurization is purchased from outside and transported to the desulfurizer storage area. The slaked lime powder transported by tank trucks is directly fed into the slaked lime storage. It is characterized in that a closed tank truck is used and pneumatic conveying is utilized. The ash storage bin can store a quantity not less than 30 days. A single bag dust collector is provided on the top of the bin. The fan outlet of the dust collector on the top of the bin is connected to the flue before the filter tube dust collector to reduce the emission points of exhaust gas.

3. A high-temperature flue gas desulfurization treatment system for a steel rolling hot rolling heating furnace according to claim 1, characterized in that: The slaked lime powder is stored in a slaked lime warehouse, transported to the flue gas inlet through a weighing small warehouse, and reacts with the acid gas. The characteristics are: an air fluidization device is arranged at the bottom of the powder storage warehouse to prevent the slaked lime powder from bridging, and a star-shaped ash discharge valve adopts frequency conversion control to adjust the dosage of the desulfurizer.

4. A high-temperature flue gas desulfurization treatment system for a steel rolling hot rolling heating furnace according to claim 1, characterized in that: The heating furnace is equipped with an online / offline dust cleaning filter tube dust collector, which is an external filtering medium and low pressure pulse filter tube dust collector, and adopts an online pulse spray cleaning method. It includes a filter tube dust collector, a spray cleaning system, an offline system, etc. The filter tube dust collector includes a structural support, a platform steel ladder, a bottom beam and a ceramic filter tube module, wherein the ceramic filter tube module includes an upper box, a middle box, an ash hopper, a flower plate, a sliding device, a cover plate, an air distribution plate, an air regulating valve, a spray device and a ceramic filter tube.

5. A high-temperature flue gas desulfurization treatment system for hot rolling heating furnace of steel rolling according to claim 1, characterized in that: The pulse cleaning system includes a compressed air bag, a blowpipe, a pulse valve, a pipeline system, and a cleaning control system. Each unit module is equipped with an air bag, and each air bag is equipped with necessary auxiliary equipment, including pipelines, accessories, shut-off valves, and control equipment. It is characterized in that the cleaning system can realize online cleaning, and the cleaning force and cleaning air volume can meet the cleaning requirements under various operating conditions. Each room is equipped with a control and monitoring system, and the main control functions include Δp pressure difference control, timing control, forced cleaning function, and single valve cleaning function.

6. A high-temperature flue gas desulfurization treatment system for hot rolling heating furnace of steel rolling according to claim 1, characterized in that: A waste ash conveying system is set up, which consists of an ash conveying fan, ash conveying pipeline, ash unloading valve, acceleration chamber, buffer bin, waste ash storage, ash storage bin top dust collector, etc., and is characterized in that the waste ash comes from the external ash discharged from the filter tube dust collector, the external ash is conveyed to the buffer bin by the ash unloading valve and then enters the acceleration chamber from the buffer bin, and is then conveyed to the ash storage by the fluidizing air generated by the ash conveying fan. The ash conveying system is provided with an anti-blocking and unblocking device, and the conveying capacity is not less than 200% of the total system conveying volume.

7. A high-temperature flue gas desulfurization treatment system for hot rolling heating furnace of steel rolling according to claim 1, characterized in that: The smoke and air duct system consists of an induced draft fan, electric damper door, smoke and air duct, etc. The induced draft fan is arranged at the end of the smoke treatment to keep the whole system under negative pressure. The induced draft fan is used to suck the smoke emitted by the heating furnace and discharge the smoke into the chimney by overcoming the resistance of the smoke duct and ceramic filter tube dust collector. The induced draft fan is equipped with a frequency conversion control device to realize automatic operation of the induced draft fan according to the negative pressure signal of the heating furnace.

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