Converter flue gas treatment system and method for recycling solid and liquid waste in steel plants

Abstract

The present invention discloses a converter flue gas treatment system and method for recycling solid and liquid waste in a steel plant. The present invention designs a black water mixing reactor and applies it to the converter flue gas treatment system. The raw material acquisition of the black water mixing reactor solves the current solid waste and waste liquid treatment problems of multiple processes, and improves the economic value and environmental value.

Description

Technical Field

[0001] The present invention relates to the field of steel, and in particular to a converter flue gas treatment system and method for recycling solid and liquid waste in a steel plant. Background Art

[0002] Steel production generates a large amount of three wastes, among which waste gas treatment has been greatly improved in environmental protection upgrades, but solid waste and waste liquid treatment are still lagging behind. There are many substances and energy in solid waste and waste liquid that can be reused. For example, steel plant dust removal ash, especially converter primary dust removal ash, blast furnace gravity dust removal ash and blast furnace bag dust removal ash all contain a high proportion of iron. At present, a small amount is used for sintering, and a large amount of ash needs to be transported out, resulting in a waste of resources. In addition, due to the lack of professional phenol-cyanide wastewater and waste oil treatment and purification capabilities, steel plants also use external transportation to solve these waste liquids, which costs money and wastes energy.

[0003] Coal-water slurry is a new, efficient and clean coal-based fuel. It is a new member of the fuel family. It is a mixture of 65%-70% coal with different particle size distribution, about 29-34% water and about 1% chemical additives. After multiple rigorous processes, impurities such as unburnable components in coal are screened out, and only the carbon essence is retained, which becomes the essence of coal-water slurry. It has the same fluidity as oil, and its calorific value is equivalent to half of that of oil. It is called liquid coal product. Coal-water slurry technology includes key technologies such as coal-water slurry preparation, storage and transportation, combustion, and additives. It is a systematic technology involving multiple disciplines. Coal-water slurry has the characteristics of high combustion efficiency and low pollutant emissions. It can be used for power station boilers, industrial boilers and industrial kilns to replace oil, gas, and coal combustion, as well as heating and domestic hot water for various buildings such as hotels, residences, hotels, and office buildings. It is an important part of today's clean coal technology. The advent of coal-water slurry originated from the world oil energy crisis in the 1970s. After the economic recession caused by the oil energy crisis, the world clearly realized that oil and natural gas, as clean energy, are not inexhaustible, and abundant coal is still the main reliable energy source in the long term. Therefore, coal liquefaction, gasification and slurry have become research topics of universal importance. Water-coal slurry is the best result of coal liquefaction and the cheapest practical technology for clean utilization of coal.

[0004] At present, water-coal slurry technology is mainly used in the processes of power plants and chemical plants. Although coal, as a non-renewable resource, is cheaper than crude oil and natural gas, it is itself the main carbon source for steel mills. Therefore, it is not economically viable for steel mills to directly use coal to make water-coal slurry.

[0005] In the early days, the main reducing agent (carbon source) for blast furnace ironmaking was coke. As the price of coke continues to rise, steel mills are committed to using blast furnace ironmaking coal injection technology to replace part of the coke to provide a cheap carbon source as a reducing agent. Among them, oil injection technology has been explored (Hu Junge, Guo Yanling, Zhou Wentao. Current status and development of blast furnace coal injection technology [J]. Anshan Technology, 2015(05):7-12.). Both coal injection technology and oil injection technology are solutions for replacing carbon sources. Although the cost is lower than that of coke, there is still a raw material cost. Moreover, oil injection and coal injection technology only provide carbon sources. In blast furnace smelting, the participation of reactant iron-containing minerals is also required. If there is a technology that can simultaneously replace coke as a carbon source and iron ore as a reactant, then the economic value of this substitution is higher.

[0006] The present invention develops a converter flue gas treatment system and method suitable for recycling and reusing solid and liquid waste energy materials in steel plants based on the physical and chemical properties of water-coal slurry. Summary of the invention

[0007] The object of the present invention is to provide a converter flue gas treatment system and method for recycling solid and liquid waste in a steel plant.

[0008] The present invention designs a black water mixing reactor and applies it to the converter flue gas treatment system. The raw material acquisition of the black water mixing reactor solves the current solid waste and waste liquid treatment problems of multiple processes, and improves the economic value and environmental value. The black water is the water-coal slurry prepared from the solid and liquid waste of the steel plant.

[0009] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0010] The first aspect of the present invention provides a converter flue gas treatment system for recycling solid and liquid waste in a steel plant, the converter flue gas treatment system comprising:

[0011] Black water mixing reactor, evaporative cooler, electrostatic precipitator unit, denitrification unit, three-way valve, first carbon dioxide separation unit, second carbon dioxide separation unit;

[0012] The upper part of the black water mixing reactor (preferably about 1 m away from the upper end outlet) is provided with a black water nozzle and a burner, the lower part is provided with a solid feeding hole, the middle section is a steam recovery section, and a heat exchange tube is wound around its outer wall;

[0013] The black water nozzle comprises a black water feed inlet, a carrier gas feed inlet and a jet outlet, and the burner comprises a feed inlet and a jet outlet; all the jet outlets are oriented toward the black water mixing reactor;

[0014] The inlet of the heat exchange tube is connected to a deaerator, and the outlet is connected to a steam drum, and the outlet of the steam drum is connected to the carrier gas feed port of the black water nozzle to provide steam as a carrier gas;

[0015] The upper port of the black water mixing reactor is connected to the inlet of the evaporative cooler through a flue, the outlet of the evaporative cooler is connected to the electrostatic precipitator unit and the denitrification unit in sequence, the outlet of the denitrification unit is connected to one interface of the three-way valve; the other two interfaces of the three-way valve are respectively connected to the first carbon dioxide separation unit and the second carbon dioxide separation unit; the carbon monoxide outlet of the first carbon dioxide separation unit is connected to the feed port of the burner of the black water mixing reactor; the carbon dioxide outlets of the first carbon dioxide separation unit and the second carbon dioxide separation unit are merged through a pipeline.

[0016] The deaerator is used to remove oxygen from boiler feed water to avoid impact on equipment and pipelines; in particular, the boiler water in the heat exchange tubes of the steam recovery section of the black water mixing reactor needs to be deoxygenated to prevent the pipelines from corroding too quickly and increase the design life of the equipment.

[0017] When the reaction temperature in the black water mixed reactor is too high, deoxygenated water (from the deaerator, also called boiler water) is introduced to cool the reactor. The boiler water from the deaerator absorbs heat through the steam recovery section to generate steam, which is sent to the steam drum for storage. The stored steam can be directly sent to the black water nozzle as carrier gas and power gas, or sent to the power pipeline in the plant area for steam power generation and power generation.

[0018] According to the converter flue gas treatment system of the present invention, preferably, a plurality of black water nozzles are arranged around the upper port of the black water mixing reactor, and the jet directions of the jet outlets of the black water nozzles are all in the tangent direction of the spiral line of the black water mixing reactor. When the plurality of black water nozzles work simultaneously, a swirl can be formed. The black water is sprayed into the reactor in a swirl manner through the black water nozzles, and fully contacts with the converter flue gas to react.

[0019] According to the converter flue gas treatment system of the present invention, preferably, pneumatic ash conveying silo pumps are provided at the bottom of the evaporative cooler and the electrostatic precipitator unit, and the outlets thereof are connected to the solid feeding hole.

[0020] According to the converter flue gas treatment system of the present invention, preferably, the carrier gas of the pneumatic ash conveying silo pump is nitrogen.

[0021] The pneumatic ash conveying silo pump is installed below the dust removal device. Nitrogen is the carrier gas source for pneumatic conveying. The ash that needs to be returned to the furnace for re-smelting is sent back to the rotary furnace through the solid feeding hole by pneumatic ash conveying for re-smelting.

[0022] According to the converter flue gas treatment system of the present invention, preferably, an induced draft fan is provided on the connecting pipeline between the electrostatic precipitator unit and the denitrification unit.

[0023] According to the converter flue gas treatment system of the present invention, preferably, the denitration unit is a denitration tower, and the denitration tower includes an air inlet, a liquid inlet and an air outlet;

[0024] The air inlet is connected to the outlet of the induced draft fan, the air outlet is connected to an interface of the three-way valve, the liquid inlet is connected to an ammonia tank, and a booster pump is arranged on the connecting pipeline.

[0025] According to the converter flue gas treatment system of the present invention, preferably, a gas compressor is provided on the connecting pipeline between the first carbon dioxide separation unit and the burner.

[0026] According to the converter flue gas treatment system of the present invention, preferably, the converter flue gas treatment system further comprises a black water preparation unit, and the black water preparation unit is used to prepare black water and provide the black water to the black water nozzle.

[0027] The black water refers to the coal-water slurry prepared from the solid and liquid waste of the steel plant. The black water preparation unit uses recycled iron-based solid waste, carbon-based solid waste, liquid carbon source and fluidized waste liquid to make coal-water slurry, which is pumped to the vicinity of the target process reactor, that is, the black water mixing reactor, through a pipeline, and is sprayed into the reactor through a black water nozzle using steam as a carrier gas for reaction.

[0028] According to the converter flue gas treatment system of the present invention, preferably, a ferromagnetic screening unit is provided at the bottom of the evaporative cooler and the electrostatic precipitator unit before the pneumatic ash conveying silo pump, and the ferromagnetic screening unit includes a magnetic outlet and a non-magnetic outlet, the magnetic outlet is connected to the pneumatic ash conveying silo pump, and the non-magnetic outlet is connected to the black water preparation unit.

[0029] Through ferromagnetic screening, the electromagnet can attract the ash with high iron content, which is sent back to the furnace for re-refining, while the ash with low iron content that cannot be attracted is recovered for the configuration of black water.

[0030] Another aspect of the present invention provides a converter flue gas treatment method for recycling solid and liquid wastes in a steel plant, which is carried out using the above converter flue gas treatment system.

[0031] According to the converter flue gas treatment method of the present invention, preferably, the converter flue gas treatment method comprises the following process:

[0032] Converter flue gas (i.e., steelmaking waste flue gas from a steelmaking furnace) enters from the bottom of the black water mixing reactor, black water is sprayed into the black water mixing reactor from the black water nozzle, and reacts with the converter flue gas to release reaction heat, which is absorbed by the heat exchange tubes of the steam recovery section and transferred to the feed water of the deaerator, the deoxygenated water in the heat tube evaporates to form steam and is sent to the steam drum for storage, and the steam stored in the steam drum is provided to the black water nozzle as a carrier gas;

[0033] The converter flue gas is reacted in the black water mixed reactor to form converter gas, and the converter gas is passed through the evaporative cooler for coarse ash sedimentation, and then passed through the electrostatic precipitator unit for fine dust removal and the denitrification unit for denitrification, and then reaches the three-way valve; the low-grade coal gas enters the first carbon dioxide separation unit to separate the carbon dioxide, and then is sent back to the black water mixed reactor through the burner for re-reaction; the high-grade coal gas enters the second carbon dioxide separation unit to separate the carbon monoxide, and is sent to the carbon chemical industry for methanol production; the carbon dioxide separated by the first carbon dioxide separation unit and the second carbon dioxide separation unit are combined and enter the carbon dioxide capture device (CCU system) for recycling.

[0034] Since the reaction process is unstable, high-grade coal gas is obtained for a period of time and low-grade coal gas for a period of time. The CO mole fraction in the low-grade coal gas is lower than 25%, and the CO mole fraction higher than 25% is high-grade coal gas.

[0035] The burner is used to inject low-grade coal gas and is provided with a ceramic ignition head and a sintered metal on the inner wall of the ceramic. At the same time, a pulse high-voltage igniter is used to ignite in the hole. It burns low-grade coal gas with <25% CO and separated CO2. The burner is designed to match the low-grade coal gas based on the flame characteristic curves of different concentrations of coal gas.

[0036] According to the converter flue gas treatment method of the present invention, preferably, the coarse ash obtained from the evaporative cooler and the fine ash obtained from the electrostatic precipitator unit are respectively subjected to ferromagnetic screening, and the ash with high iron content is transported to the solid feeding hole by a pneumatic ash silo pump and sent back to the black water mixing reactor for re-refining, and the ash with low iron content is used for the preparation of black water.

[0037] The black water is prepared using solid and liquid waste from a steel plant, and the solid and liquid waste from the steel plant includes iron-based solid waste, carbon-based solid waste, liquid carbon source and fluidized waste liquid.

[0038] The preparation of the black water comprises the following processes:

[0039] 1) Raw material acquisition, including iron-based solid waste, carbon-based solid waste, liquid carbon source and fluidized waste liquid;

[0040] 2) crushing the solid waste into solid waste particles;

[0041] 3) Turning organic wastewater and oily waste liquid, which have high treatment costs, into emulsified fluidizing agents;

[0042] 4) Using the emulsifying fluidizer to fluidize the solid waste particles to prepare a carbon-based iron-containing slurry.

[0043] Iron-based solid waste comes from: gravity dust removal ash from the lower part of blast furnace gravity dust removal, blast furnace gas dust removal ash obtained in the blast furnace gas bag dust removal ash bin, primary dust removal coarse ash from the converter steelmaking plant and primary dust removal fine ash from the primary dust removal area. Since some of these processes use dry ash unloading (ash unloading by suction truck, no exogenous moisture, only ash self-contained water) and some factories use humidified ash unloading (adding 25% moisture), they are stored separately when transported to the black water preparation unit so that they can be classified and quantitatively added during the subsequent preparation.

[0044] Carbon-based solid waste comes from: waste carbon outside the factory and surrounding biomass, including various waste wood chips, waste wood packaging, waste paper outside the factory, straw, husks and other biomass outside the factory.

[0045] Waste liquid includes liquid carbon source and fluidized waste liquid, including: blast furnace gas waste water obtained from the gas drainer below the blast furnace gas low-pressure pipeline network; coke oven gas waste water obtained from the coke oven gas pipeline network is mainly used as a fluidizing and dispersant for slurry; waste hydraulic oil obtained from each hydraulic station and waste lubricating oil obtained from the lubrication station are used as liquid carbon sources to adjust the total carbon content of the slurry. They are sent to the black water preparation unit for physical and chemical testing and the components in the container are recorded.

[0046] When the factory has abundant carbon-based solid waste and waste liquid, it can also make iron-free carbon-based slurry separately and send it to the factory's power generation boiler or heating boiler as fuel.

[0047] The beneficial effects of the present invention include:

[0048] 1) The present invention will develop a black water mixing reactor for application in the converter process and design a converter flue gas treatment system, thereby realizing the recycling of solid and liquid wastes from steel mills, replacing coke as a carbon source, and having high technical and economic value.

[0049] 2) The raw material acquisition of black water used in the system and method of the present invention solves the current problem of treating solid waste and waste liquid in multiple processes, further improving the economic value and environmental value of the present invention.

[0050] 3) The black water used in the system and method of the present invention is a fluidized product and can be transported by pipeline or pumping. The transportation cost is cheaper, more convenient and safer than solid transportation.

[0051] 4) The system and method of the present invention can form a carbon cycle, continuously enriching carbon dioxide for recycling.

[0052] 5) The black water mixed reactor of the present invention can not only solve the solid waste and liquid waste problems of steel plants, but also recover steam as a substitute for waste heat boilers. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1The schematic diagram of a converter flue gas treatment system for recycling solid and liquid wastes in a steel plant in a preferred embodiment.

[0054] Description of reference numerals:

[0055] 1. Steelmaking furnace;

[0056] 2. Black water mixing reactor;

[0057] 3. Black water nozzle;

[0058] 4. Burner;

[0059] 5. Solid feeding hole;

[0060] 6. Heat exchange tube;

[0061] 7. Deaerator;

[0062] 8. Steam drum;

[0063] 9. Evaporative cooler;

[0064] 10. Electrostatic precipitator;

[0065] 11. Induced draft fan;

[0066] 12. Denitrification tower;

[0067] 13. Booster pump;

[0068] 14. Ammonia tank;

[0069] 15. Three-way valve;

[0070] 16. A first carbon dioxide separation unit;

[0071] 17. Gas compressor;

[0072] 18. A second carbon dioxide separation unit;

[0073] 19 / 20. Pneumatic ash silo pump. DETAILED DESCRIPTION

[0074] In order to explain the present invention more clearly, the present invention is further described below in conjunction with preferred embodiments. It should be understood by those skilled in the art that the following specific description is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0075] The present invention provides a preferred embodiment as follows: Figure 1 As shown, a converter flue gas treatment system for recycling solid and liquid waste in a steel plant, the converter flue gas treatment system comprises:

[0076] Black water mixing reaction furnace 2, evaporative cooler 9, electrostatic precipitator 10, denitration tower 12, three-way valve 15, first carbon dioxide separation unit 16, second carbon dioxide separation unit 18;

[0077] The upper part of the black water mixing reactor 2 is provided with a black water nozzle 3 and a burner 4, the lower part is provided with a solid feeding hole 5, the middle section is a steam recovery section, and a heat exchange tube 6 is wound around its outer wall;

[0078] The black water nozzle 3 includes a black water feed port, a carrier gas feed port and a jet outlet, and the burner 4 includes a feed port and a jet outlet; all the jet outlets are oriented toward the black water mixing reactor 2;

[0079] The inlet of the heat exchange tube 6 is connected to a deaerator 7, and the outlet is connected to a steam drum 8. The outlet of the steam drum 8 is connected to the carrier gas feed port of the black water nozzle 3 to provide steam as a carrier gas.

[0080] The upper port of the black water mixing reaction furnace 2 is connected to the inlet of the evaporative cooler 9 through a flue, and the outlet of the evaporative cooler 9 is connected to the electrostatic precipitator 10 and the denitrification tower 12 in sequence.

[0081] An induced draft fan 11 is provided on the connecting pipeline between the electrostatic precipitator 10 and the denitration tower 12. The denitration tower 12 includes an air inlet, a liquid inlet and an air outlet; the air inlet is connected to the outlet of the induced draft fan 11, the air outlet is connected to an interface of a three-way valve 15, the liquid inlet is connected to an ammonia water tank 14, and a booster pump 13 is provided on the connecting pipeline.

[0082] The other two interfaces of the three-way valve 15 are respectively connected to the first carbon dioxide separation unit 16 and the second carbon dioxide separation unit 18; the carbon monoxide outlet of the first carbon dioxide separation unit 16 is connected to the feed port of the burner 4 of the black water mixing reactor 2, and a gas compressor 17 is arranged on the connecting pipeline. The carbon dioxide outlets of the first carbon dioxide separation unit 16 and the second carbon dioxide separation unit 18 are combined through a pipeline.

[0083] Preferably, a plurality of black water nozzles 3 are arranged around the upper port of the black water mixing reactor 2, and the jet directions of the jet outlets of the black water nozzles 3 are all in the tangent direction of the spiral line of the black water mixing reactor 2. When the plurality of black water nozzles 3 work simultaneously, a swirl can be formed. Black water is sprayed into the reactor in a swirl manner through the black water nozzles 3, and fully contacts with the converter flue gas for reaction.

[0084] The bottom of the evaporative cooler 9 and the electrostatic precipitator 10 are both provided with pneumatic ash conveying bin pumps 19 and 20, and their outlets are both connected to the solid feeding hole 5. The carrier gas of the pneumatic ash conveying bin pumps 19 and 20 is nitrogen.

[0085] The pneumatic ash conveying silo pump is installed below the dust removal device. Nitrogen is the carrier gas source for pneumatic conveying. The ash that needs to be returned to the furnace for re-smelting is sent back to the rotary furnace through the solid feeding hole by pneumatic ash conveying for re-smelting.

[0086] The converter flue gas treatment system further includes a black water preparation unit (not shown in the figure), which is used to prepare black water and provide the black water to the black water nozzle 3.

[0087] A ferromagnetic screening unit (not shown) is provided at the bottom of the evaporative cooler 9 and the electrostatic precipitator 10 before the pneumatic ash conveying silo pump 19 / 20, which includes a magnetic outlet and a non-magnetic outlet. The magnetic outlet is connected to the pneumatic ash conveying silo pump 19 / 20, and the non-magnetic outlet is connected to the black water preparation unit.

[0088] Through ferromagnetic screening, the electromagnet can attract the ash with high iron content, which is sent back to the furnace for re-refining, while the ash with low iron content that cannot be attracted is recovered for the configuration of black water.

[0089] The process method using the above converter flue gas treatment system includes the following processes:

[0090] The converter flue gas (i.e., steelmaking waste flue gas from the steelmaking furnace 1) enters from the bottom of the black water mixing reactor 2, and black water is sprayed into the black water mixing reactor 2 from the black water nozzle 3 using steam as a carrier gas, and reacts with the converter flue gas to release reaction heat, which is absorbed by the heat exchange tube 6 of the steam recovery section and transferred to the feed water of the deaerator. The deoxygenated water in the heat exchange tube 6 evaporates to form steam and is sent to the steam drum 8 for storage. The steam stored in the steam drum 8 is provided to the black water nozzle 3 as a carrier gas.

[0091] The converter flue gas is reacted in the black water mixed reactor 2 to form converter gas. The converter gas is subjected to coarse ash precipitation through the evaporative cooler 9. The converter gas after coarse ash precipitation is then subjected to fine dust removal by the electrostatic precipitator 10 and denitrification by the denitrification tower 12, and then reaches the three-way valve 15. The low-grade gas enters the first carbon dioxide separation unit 16 to separate carbon dioxide and is sent back to the black water mixed reactor 2 through the burner 4 for re-reaction; the high-grade gas enters the second carbon dioxide separation unit 18 to separate carbon monoxide, which is sent to the carbon chemical industry for methanol production; the carbon dioxide separated by the first carbon dioxide separation unit 16 and the second carbon dioxide separation unit 18 are combined and sent to the carbon dioxide capture device (CCU system) for recycling.

[0092] Since the reaction process is unstable, high-grade coal gas is obtained for a period of time and low-grade coal gas for a period of time. The CO mole fraction in the low-grade coal gas is lower than 25%, and the CO mole fraction higher than 25% is high-grade coal gas.

[0093] Preferably, the coarse ash obtained from the evaporative cooler and the fine ash obtained from the electrostatic precipitator unit are respectively subjected to ferromagnetic screening, and the ash with high iron content is transported to the solid feeding hole through a pneumatic ash silo pump and sent back to the black water mixing reactor for re-refining, while the ash with low iron content is used for the preparation of black water.

[0094] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A converter flue gas treatment system for recycling solid and liquid waste in a steel plant, characterized in that: The converter flue gas treatment system includes: Black water mixing reactor, evaporative cooler, electrostatic precipitator unit, denitrification unit, three-way valve, first carbon dioxide separation unit, second carbon dioxide separation unit; The upper part of the black water mixing reactor is provided with a black water nozzle and a burner, the lower part is provided with a solid feeding hole, the middle section is a steam recovery section, and a heat exchange tube is wound around its outer wall; The black water nozzle comprises a black water feed port, a carrier gas feed port and a jet outlet, and the burner comprises a feed port and a jet outlet; all the jet outlets are oriented toward the black water mixing reactor; and a plurality of black water nozzles are arranged around the upper port of the black water mixing reactor, and the jet directions of the jet outlets of the black water nozzles are all tangent to the spiral line of the black water mixing reactor; The inlet of the heat exchange tube is connected to a deaerator, and the outlet is connected to a steam drum, and the outlet of the steam drum is connected to the carrier gas feed port of the black water nozzle; The upper port of the black water mixing reactor is connected to the inlet of the evaporative cooler through a flue, the outlet of the evaporative cooler is connected to the electrostatic precipitator unit and the denitration unit in sequence, the outlet of the denitration unit is connected to one interface of the three-way valve; the other two interfaces of the three-way valve are respectively connected to the first carbon dioxide separation unit and the second carbon dioxide separation unit; the carbon monoxide outlet of the first carbon dioxide separation unit is connected to the feed port of the burner of the black water mixing reactor; the carbon dioxide outlets of the first carbon dioxide separation unit and the second carbon dioxide separation unit are combined through a pipeline; The bottom of the evaporative cooler and the electrostatic precipitator unit are both provided with a pneumatic ash conveying bin pump, and the outlets thereof are both connected to the solid feeding hole; The converter flue gas treatment system further comprises a black water preparation unit, which is used to prepare black water and provide the black water to the black water nozzle; A ferromagnetic screening unit is provided at the bottom of the evaporative cooler and the electrostatic precipitator unit before the pneumatic ash conveying silo pump. The ferromagnetic screening unit includes a magnetic outlet and a non-magnetic outlet. The magnetic outlet is connected to the pneumatic ash conveying silo pump, and the non-magnetic outlet is connected to the black water preparation unit.

2. The converter flue gas treatment system according to claim 1, characterized in that: The carrier gas of the pneumatic ash silo pump is nitrogen.

3. The converter flue gas treatment system according to claim 1, characterized in that: An induced draft fan is arranged on the connecting pipeline between the electrostatic precipitator unit and the denitration unit.

4. The converter flue gas treatment system according to claim 3, characterized in that: The denitration unit is a denitration tower, which includes an air inlet, a liquid inlet and an air outlet; The air inlet is connected to the outlet of the induced draft fan, the air outlet is connected to an interface of the three-way valve, the liquid inlet is connected to an ammonia tank, and a booster pump is arranged on the connecting pipeline.

5. The converter flue gas treatment system according to claim 1, characterized in that: A gas compressor is provided on the connecting pipeline between the first carbon dioxide separation unit and the burner.

6. A method for treating converter flue gas for recycling solid and liquid waste in a steel plant, which is carried out using the converter flue gas treatment system according to any one of claims 1 to 5.

7. The converter flue gas treatment method according to claim 6, characterized in that: Converter flue gas treatment method The process includes: The converter flue gas enters from the bottom of the black water mixing reactor, and the black water is sprayed into the black water mixing reactor from the black water nozzle, and reacts with the converter flue gas to release reaction heat, which is absorbed by the heat exchange tube of the steam recovery section and transferred to the feed water of the deaerator. The deoxygenated water in the heat tube evaporates to form steam and is sent to the steam drum for storage. The steam stored in the steam drum is provided to the black water nozzle as a carrier gas; The converter flue gas is reacted in the black water mixed reactor to form converter gas, and the converter gas is subjected to coarse ash sedimentation in the evaporative cooler, and then is subjected to fine dust removal in the electrostatic precipitator unit and denitrification in the denitrification unit, and then reaches the three-way valve; the low-grade gas enters the first carbon dioxide separation unit to separate carbon dioxide, and then is sent back to the black water mixed reactor through the burner for re-reaction; the high-grade gas enters the second carbon dioxide separation unit to separate carbon monoxide, and is sent to a carbon chemical industry for methanol production; the carbon dioxide separated by the first carbon dioxide separation unit and the second carbon dioxide separation unit are combined and sent to a carbon dioxide capture device for recycling; The coarse ash obtained from the evaporative cooler and the fine ash obtained from the electrostatic precipitator unit are respectively subjected to ferromagnetic screening. The ash with high iron content is transported to the solid feeding hole through a pneumatic ash conveying silo pump and sent back to the black water mixing reactor for re-refining, while the ash with low iron content is used for the preparation of the black water.

Images