Process and system for coupling metallurgical slag granulation, metallurgical flue gas desulfurization and denitrification and carbon capture

Abstract

The invention provides a metallurgical slag granulation and metallurgical flue gas desulfurization and denitrification and carbon capture coupled technology and system, and belongs to the technical field of flue gas desulfurization and denitrification. Metallurgical slag granulation and metallurgical flue gas desulfurization and denitrification and carbon capture processes are coupled, flue gas is introduced into a slag pile obtained through granulation in the metallurgical slag granulation process, and the slag pile is subjected to carbon capture and carbon capture; enabling sulfur oxide gas, nitrogen oxide gas and carbon oxide gas contained in the flue gas to react with alkaline substances in the slag particles by utilizing the waste heat of the slag particles and the flue gas to generate inorganic salt so as to absorb harmful gas in the flue gas and complete desulfurization, denitrification and carbon sequestration of the blast furnace flue gas, and then carrying out tail gas treatment. According to the process, the desulfurization rate reaches 95% or above, the denitration rate reaches 85% or above, and the carbon dioxide capture rate reaches 95% or above.

Description

Technical Field

[0001] The present invention relates to the technical field of flue gas desulfurization and denitrification, and in particular to a process and system for coupling metallurgical slag granulation with metallurgical flue gas desulfurization and denitrification and carbon capture. Background Art

[0002] The sintering process of steel smelting emits a large amount of SO x 、NO x 、CO x According to statistics, each sintering process of 1 ton of iron ore will produce about 4000-6000 mL of flue gas. If it is directly discharged into the atmosphere, SO x 、NO x Acidic gases such as SO2 can cause serious harm to the environment (such as acid rain), while CO2 can further accelerate global warming. Therefore, it is necessary to remove SO2 from flue gas. x 、NO x 、CO x And other harmful gases to protect the environment.

[0003] Prior art flue gas desulfurization and denitrification methods include wet treatments (such as limestone-gypsum and ammonia methods) and dry / semi-dry treatments (such as spray drying, circulating fluidized bed (CFB), and activated carbon / coke adsorption). For example, Chinese Patent Publication No. CN101695627B provides a dry flue gas purification method and apparatus for simultaneous desulfurization and denitrification. Using a circulating fluidized bed as a reactive absorber, a highly oxidizing, soluble absorbent additive is dissolved in process water. This is pumped through a high-pressure water pump in the process water system to an atomizing spray gun, where it is sprayed into the absorber along with cooled and humidified water. The additive's oxidizing and catalytic effects quickly react with NO in the flue gas to convert it into water-soluble NO₂. This NO₂ is then absorbed and removed along with SO₂ by a calcium-based absorbent added to the absorber, achieving simultaneous desulfurization and denitrification. This method sprays the highly oxidizing additive into the reactive absorber via the process water system, synthesizing a highly dispersed, highly active "oxygen-enriched" absorbent in situ. This simplifies the absorbent preparation process and significantly improves the additive's effectiveness. However, this method requires large equipment investment, which increases the cost of flue gas treatment.

[0004] In view of this, it is necessary to design a process and system that couples metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture to solve the above problems. Summary of the Invention

[0005] In view of the technical problems existing in the background technology, the present application provides a process and system for coupling metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture. The process couples metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture processes, and utilizes alkaline substances such as CaO, MgO, Ca(OH)2, Mg(OH)2 contained in metallurgical slag to absorb SO in flue gas. x 、NO x 、CO x The process simultaneously removes pollutants such as sulfur and nitrogen oxides, while also capturing carbon, ensuring flue gas meets emission standards. Furthermore, the free CaO and MgO content in the slag particles is reduced, facilitating further recycling. This process achieves a desulfurization rate exceeding 95%, a denitrification rate exceeding 85%, and a carbon dioxide capture rate exceeding 95%.

[0006] On the first aspect, the embodiment of the present application provides a process for coupling metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture, which couples the metallurgical slag granulation with the metallurgical flue gas desulfurization, denitrification and carbon capture processes. During the metallurgical slag granulation process, the flue gas is passed into the slag pile obtained by granulation, and the waste heat of the slag particles and the flue gas is used to cause the sulfur oxide gas, nitrogen oxide gas and carbon oxide gas contained in the flue gas to react with the alkaline substances in the slag particles to generate inorganic salts to absorb harmful gases in the flue gas, thereby completing the desulfurization, denitrification and carbon fixation of the blast furnace flue gas, and then performing tail gas treatment.

[0007] Furthermore, the alkaline substance includes CaO, MgO, Ca(OH)2, Mg(OH)2, and the inorganic salt includes CaSO4, Ca(NO2)2, MgSO4, Mg(NO2)2, CaCO3, and MgCO3.

[0008] Furthermore, the metallurgical slag granulation process is as follows: the molten metallurgical slag flows out through the port at the bottom of the slag ladle, is granulated into fine particles under the action of the jet medium sprayed from the jet nozzle, and falls to the bottom of the granulation bin under natural gravity.

[0009] Furthermore, the jet medium is liquid, gas or a gas-liquid mixture; the jet pressure when the jet medium is liquid is 50-100 MPa, the jet pressure when the jet medium is gas is 0.5-5 MPa, and the jet pressure when the jet medium is a gas-liquid mixture is 5-50 MPa.

[0010] Furthermore, the jet medium is a mixture of one or more of water, air, nitrogen, and water vapor.

[0011] Furthermore, the process of flue gas desulfurization, denitrification and carbon capture is as follows: the flue gas is first cooled and dust-removed, and then enters the slag pile accumulated at the bottom of the granulation bin through the air vents at the bottom of the granulation bin, reacts with the slag pile and continues to flow upward, forming convection with the falling fine particles, and finally flows into the exhaust gas treatment device from the side or top of the granulation bin.

[0012] Furthermore, the amount of flue gas processed per kilogram of slag particles is 5-7.5Nm 3 / h.

[0013] Furthermore, the tail gas treatment includes using a cyclone dust collector for primary dust removal and using a bag dust collector for secondary dust removal.

[0014] In a second aspect, the present invention provides a system for coupling metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture, including a metallurgical slag granulation device, a flue gas conveying device and an exhaust gas treatment device, wherein: The metallurgical slag granulation device includes a granulation bin and a slag ladle arranged above the granulation bin. The bottom of the slag ladle is provided with a port for the metallurgical slag to flow out. The port extends into the granulation bin and extends to the vicinity of the jet nozzle. The jet nozzle is connected to an external pressure pump through a pipeline. The smoke conveying device includes an air inlet, a gas pipeline connecting the air inlet with the air vent at the bottom of the granulating bin, and a gas valve arranged at the air inlet end of the gas pipeline; The exhaust gas post-processing device includes a cyclone dust collector connected to the top or side of the granulation bin, a bag dust collector connected to the exhaust port of the cyclone dust collector, and an exhaust gas outlet connected to the exhaust port of the bag dust collector.

[0015] Furthermore, the bottom of the granulation bin is also provided with air holes for flue gas input and a funnel for slag particles to be discharged; the granulation bin is a closed granulation bin; the metallurgical slag granulation device, the flue gas conveying device and the tail gas treatment device are combined to obtain a metallurgical slag granulation and metallurgical flue gas desulfurization, denitrification and carbon capture coupling system, which is a closed system in which the internal gas is fully isolated from the external environment.

[0016] The beneficial effects of this application are as follows: The present application provides a process and system for coupling metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture. The process couples metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture processes, and utilizes alkaline substances such as CaO, MgO, Ca(OH)2, and Mg(OH)2 contained in the metallurgical slag to absorb SO in the flue gas. x 、NO x 、CO xThe process removes pollutants such as sulfur and nitrogen oxides, while simultaneously achieving desulfurization, denitrification, and carbon capture, ensuring that flue gas meets emission standards. The process achieves a desulfurization rate of over 95%, a denitrification rate of over 85%, and a carbon dioxide capture rate of over 95%.

[0017] This application uses high-pressure jet granulation to granulate molten metallurgical slag into uniform, fine particles. During the granulation process, flue gas is introduced through air holes at the bottom of the granulation bin and flows upward through the slag pile at a temperature of 100-300°C, facilitating a thorough and efficient reaction between the flue gas and the slag. This treatment reduces the free CaO and MgO content in the slag particles, facilitating further recycling. For example, when the slag particles are used as construction materials or roadbed materials, the reduced free CaO and MgO content improves the material's stability.

[0018] The system provided herein couples metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification, and carbon capture. The system comprises a metallurgical slag granulation unit, a flue gas conveying unit, and an exhaust gas treatment unit, resulting in a closed system that fully isolates the internal gas from the external environment. This arrangement ensures that the flue gas does not leak into the environment during the treatment process. After exhaust gas treatment, the system can be discharged directly or recycled after dehydration, depending on the exhaust gas composition.

[0019] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] To more clearly illustrate the technical solution of this application, the following is a brief introduction to the drawings used in this application. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0021] Figure 1 Schematic diagram of the system for coupling metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture in Example 1 of the present application. DETAILED DESCRIPTION

[0022] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0024] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0025] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0026] In the description of the embodiments of this application, the term "and / or" is merely a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of this application can be understood according to specific circumstances.

[0027] The sintering process of steel smelting emits a large amount of SO x 、NO x 、CO x According to statistics, each sintering process of 1 ton of steel will produce about 4000-6000 mL of flue gas. If it is directly discharged into the atmosphere, SO x 、NO x Acidic gases such as SO2 can cause serious harm to the environment (such as acid rain), while CO2 can further accelerate global warming. Therefore, it is necessary to remove SO2 from flue gas. x 、NO x 、CO x However, the equipment investment of the desulfurization and denitrification methods in the prior art is large, which increases the cost of flue gas treatment.

[0028] In order to solve the above technical problems, the present application provides a process and system for coupling metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture. The process couples metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture processes, and utilizes alkaline substances such as CaO, MgO, Ca(OH)2, and Mg(OH)2 contained in the metallurgical slag to absorb SO in the flue gas. x 、NO x 、CO x The process removes pollutants such as sulfur and nitrogen, and simultaneously achieves desulfurization, denitrification, and carbon capture, ensuring that flue gas meets emission standards. In addition, the content of free CaO and MgO in the slag particles is reduced, facilitating further recycling.

[0029] In the first aspect, the embodiment of the present application provides a process for coupling metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture. The process couples metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture processes. During the metallurgical slag granulation process, the flue gas is introduced into the slag pile 15 obtained by granulation, and the waste heat of the slag particles and the flue gas is used to reduce the sulfur oxide gas (SO x ), nitrogen oxide gas (NO x ) and carbon oxide gases (CO x ) reacts with alkaline substances in the slag to form inorganic salts that absorb harmful gases in the flue gas, completing the desulfurization, denitrification, and carbon fixation of the blast furnace flue gas, and then proceeding to tail gas treatment. The alkaline substances in the slag include CaO, MgO, Ca(OH)2, and Mg(OH)2. The inorganic salts generated by the reaction between the flue gas and the slag include CaSO4, Ca(NO2)2, MgSO4, Mg(NO2)2, CaCO3, and MgCO3.

[0030] Coupling metallurgical slag pelletizing with metallurgical flue gas desulfurization, denitrification, and carbon capture processes can not only absorb harmful gases from the flue gas, completing the desulfurization, denitrification, and carbon fixation of blast furnace flue gas, but also convert free CaO, MgO, Ca(OH)2, and Mg(OH)2 in the slag particles into inorganic salts, facilitating the recycling of the slag particles. For example, when the slag particles are used as construction materials or roadbed materials, the reduced free CaO and MgO content helps improve the material's stability.

[0031] In the embodiment of the present application, the metallurgical slag granulation process is as follows: the molten metallurgical slag flows out through the port at the bottom of the slag ladle 11, is granulated into fine particles under the action of the jet medium ejected by the jet nozzle 13, and falls to the bottom of the granulation bin 14 by natural gravity, and is deposited as a slag pile 15. The slag pile 15 can be a slag particle pile or a slag slurry. The process of flue gas desulfurization, denitrification and carbon capture is as follows: the flue gas is first cooled (to 100-300 ° C), dust-removed, and then enters the slag pile 15 accumulated at the bottom of the granulation bin 14 through the air vents 17 at the bottom of the granulation bin 14. After reacting with the slag pile 15, it continues to flow upward, forming convection with the falling fine particles, and finally flows into the exhaust gas treatment device 3 from the side or top of the granulation bin 14.

[0032] In the embodiment of the present application, exhaust gas treatment includes primary dust removal using a cyclone dust collector 31 and secondary dust removal using a bag filter 32. The exhaust gas after exhaust treatment can be discharged directly or recycled after dehydration, depending on its composition. If the exhaust gas contains energy gases such as CO and H2, the energy gas can be further recovered through pressure swing adsorption (PSA) or other gas separation / purification technologies for use in heating, power generation, or chemical production.

[0033] In the embodiments of the present application, the jet medium is a liquid, a gas, or a gas-liquid mixture, preferably a mixture of one or more of water, air, nitrogen, and water vapor. The jet pressure is 50-100 MPa when the jet medium is a liquid, 0.5-5 MPa when the jet medium is a gas, and 5-50 MPa when the jet medium is a gas-liquid mixture.

[0034] In the embodiment of the present application, the amount of flue gas processed per kilogram of slag particles is 5-7.5Nm 3 / h.

[0035] In the embodiment of the present application, the reaction temperature of the flue gas and the slag pile 15 is 200-300°C.

[0036] Second, please refer to Figure 1 As shown, an embodiment of the present application provides a system for coupling metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture, including a metallurgical slag granulation device 1, a flue gas conveying device 2 and an exhaust gas treatment device 3.

[0037] The metallurgical slag granulation device 1 includes a granulation bin 14 and a slag ladle 11 located above the granulation bin 14. The bottom of the slag ladle 11 is provided with a port for the metallurgical slag to flow out. The port extends into the granulation bin 14 and to the vicinity of a jet nozzle 13. The jet nozzle 13 is connected to an external pressure pump 12 via a pipe. The bottom of the granulation bin 14 is also provided with a vent 17 for flue gas input and a funnel 16 for the discharge of slag particles.

[0038] The smoke conveying device 2 includes an air inlet 21, a gas pipeline 23 connecting the air inlet 21 with the air vent 17 at the bottom of the granulating bin 14, and a gas valve 22 provided at the air inlet end of the gas pipeline 23. The gas valve 22 is used to control the gas flow.

[0039] The exhaust gas post-processing device includes a cyclone dust collector 31 connected to the top or side of the granulation bin 14, a bag dust collector 32 connected to the exhaust port of the cyclone dust collector 31, and an exhaust gas outlet 33 connected to the exhaust port of the bag dust collector 32.

[0040] In the embodiment of the present application, the granulation bin 14 is a closed granulation bin 14. The metallurgical slag granulation device, the flue gas conveying device 2 and the tail gas treatment device 3 are combined to obtain a metallurgical slag granulation system coupled with metallurgical flue gas desulfurization, denitrification and carbon capture, which is a closed system with internal gas fully isolated from the external environment.

[0041] Some specific examples are listed below. It should be noted that the examples described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used without manufacturer's indication are all commercially available conventional products.

[0042] Example 1 Example 1 provides a process for coupling metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification, and carbon capture. First, the blast furnace slag is transferred to the slag bag 11 at the top of the granulation bin 14. Water is used as the jet medium, and the pressure pump 12 is turned on and the pressure is set to 85 MPa. The molten metallurgical slag flows out through the port at the bottom of the slag bag 11. Under the action of the high-pressure water jet sprayed by the jet nozzle 13, it is granulated into fine particles and falls to the bottom of the granulation bin 14 under natural gravity. The fine slag particles obtained by granulation are mixed with water to form a slag slurry. Then, the gas valve 22 is opened to input the metallurgical sintering flue gas that has been cooled and dust-removed into the slag pile 15 accumulated at the bottom of the granulation bin 14 through the air vent 17 at the bottom of the granulation bin 14, so that the sulfur oxide gas (SO x ), nitrogen oxide gas (NO x ) and carbon oxide gases (CO x ) reacts with the alkaline substances in the slag particles to form inorganic salts to absorb harmful gases in the flue gas, completing the desulfurization, denitrification and carbon fixation of the blast furnace flue gas. Then, a cyclone dust collector 31 is used for primary dust removal, and a bag dust collector 32 is used for secondary dust removal, and finally the tail gas is discharged. The metallurgical slag processing capacity in Example 1 is 20 tons / h, and 10Nm3 of metallurgical slag is processed for every 2 kg of metallurgical slag. 3 / h.

[0043] The system used in Example 1 is shown in Figure 1 As shown, it includes a metallurgical slag granulating device 1, a flue gas conveying device 2 and a tail gas treatment device 3.

[0044] The metallurgical slag granulation device 1 includes a granulation bin 14 and a slag ladle 11 located above the granulation bin 14. The bottom of the slag ladle 11 is provided with a port for the metallurgical slag to flow out. The port extends into the granulation bin 14 and to the vicinity of a jet nozzle 13. The jet nozzle 13 is connected to an external pressure pump 12 via a pipe. The bottom of the granulation bin 14 is also provided with a vent 17 for flue gas input and a funnel 16 for the discharge of slag particles.

[0045] The smoke conveying device 2 includes an air inlet 21, a gas pipeline 23 connecting the air inlet 21 with the air vent 17 at the bottom of the granulating bin 14, and a gas valve 22 provided at the air inlet end of the gas pipeline 23. The gas valve 22 is used to control the gas flow.

[0046] The exhaust gas post-processing device includes a cyclone dust collector 31 connected to the side of the granulation bin 14, a bag dust collector 32 connected to the exhaust port of the cyclone dust collector 31, and an exhaust gas outlet 33 connected to the exhaust port of the bag dust collector 32.

[0047] In Example 1, the composition changes of the metallurgical sintering flue gas before and after treatment are shown in Table 1, and the composition changes of the slag particles before and after treatment are shown in Table 2.

[0048] Table 1. Changes in metallurgical sintering flue gas composition in Example 1 Table 2. Changes in slag composition in Example 1 Please refer to Table 1 and Table 2 together. After processing this application, SO x 、NO x The removal rates of 247 carbon dioxide, 284 carbon dioxide and 284 carbon dioxide reached 98.5%, 87% and 97.5% respectively, meeting the emission standards. At the same time, the contents of free CaO and MgO in the slag particles were greatly reduced, and the conversion rates reached 53.8% and 44.4% respectively.

[0049] Example 2 The difference between Example 2 and Example 1 is that the jet medium is nitrogen and water, and the pressure of the high-pressure nitrogen-water jet is 12 MPa. The other parts are the same as Example 1 and will not be repeated here. The metallurgical slag processing capacity in Example 2 is 30 tons / h, and 20 Nm3 is processed for every 3 kg of metallurgical slag. 3 / h.

[0050] In Example 2, the composition changes of the metallurgical sintering flue gas before and after treatment are shown in Table 3, and the composition changes of the slag particles before and after treatment are shown in Table 4.

[0051] Table 3. Changes in metallurgical sintering flue gas composition in Example 2 Table 4. Changes in slag composition in Example 2 Please refer to Table 1 and Table 2 together, you can see that after the processing of this application, SO x 、NO x The removal rates of 247.7%, 28.7% and 29.8% of CO2 reached 97.6%, 87.4% and 96.4% respectively, meeting the emission standards. At the same time, the contents of free CaO and MgO in the slag particles were greatly reduced, and the conversion rates reached 50% and 41.7% respectively.

[0052] Example 3 The difference between Example 3 and Example 1 is that the pressure of the high-pressure water jet is set to 55 MPa. The other parts are the same as Example 1 and will not be repeated here. The metallurgical slag processing capacity in Example 3 is 40 tons / h, and 30 Nm3 is processed for every 4 kg of metallurgical slag. 3 / h.

[0053] In Example 3, the composition changes of the metallurgical sintering flue gas before and after treatment are shown in Table 5, and the composition changes of the slag particles before and after treatment are shown in Table 6.

[0054] Table 5. Changes in metallurgical sintering flue gas composition in Example 3 Table 6. Changes in slag composition in Example 3 Please refer to Table 1 and Table 2 together, you can see that after the processing of this application, SO x 、NO x The removal rates of 247.8%, 28.7% and 31.7% of CO2 reached 96.3%, 86.7% and 97.2% respectively, meeting the emission standards. At the same time, the contents of free CaO and MgO in the slag particles were greatly reduced, and the conversion rates reached 50% and 53.8% respectively.

[0055] In summary, the present application provides a process for coupling metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture, which couples metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture processes, and utilizes alkaline substances such as CaO, MgO, Ca(OH)2, and Mg(OH)2 contained in metallurgical slag to absorb SO in flue gas. x 、NO x 、CO xThe present application also provides a system for coupling metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification, and carbon capture, comprising a closed system formed by combining a metallurgical slag granulation device, a flue gas conveying device, and an exhaust gas treatment device. Through the aforementioned process and system, the present application achieves a desulfurization rate exceeding 95%, a denitrification rate exceeding 85%, and a carbon dioxide capture rate exceeding 95%.

[0056] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A process for coupling metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture, characterized in that: The metallurgical slag granulation is coupled with the metallurgical flue gas desulfurization, denitrification and carbon capture process. During the metallurgical slag granulation process, the flue gas is introduced into the slag pile obtained by granulation. The waste heat of the slag particles and the flue gas is used to make the sulfur oxide gas, nitrogen oxide gas and carbon oxide gas contained in the flue gas react with the alkaline substances in the slag particles to generate inorganic salts to absorb harmful gases in the flue gas, thereby completing the desulfurization, denitrification and carbon fixation of the blast furnace flue gas, and then carrying out tail gas treatment.

2. The process for coupling metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture according to claim 1, characterized in that: The alkaline substances include CaO, MgO, Ca(OH)2, Mg(OH)2, and the inorganic salts include CaSO4, Ca(NO2)2, MgSO4, Mg(NO2)2, CaCO3, and MgCO3.

3. The process for coupling metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture according to claim 1, characterized in that: The metallurgical slag granulation process is as follows: the molten metallurgical slag flows out through the port at the bottom of the slag ladle, is granulated into fine particles under the action of the jet medium sprayed from the jet nozzle, and falls to the bottom of the granulation bin under natural gravity.

4. The process for coupling metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture according to claim 3, characterized in that: The jet medium is liquid, gas or a gas-liquid mixture; the jet pressure when the jet medium is liquid is 50-100 MPa, the jet pressure when the jet medium is gas is 0.5-5 MPa, and the jet pressure when the jet medium is a gas-liquid mixture is 5-50 MPa.

5. The process for coupling metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture according to claim 4, characterized in that: The jet medium is a mixture of one or more of water, air, nitrogen and water vapor.

6. The process for coupling metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture according to claim 1, characterized in that: The process of flue gas desulfurization, denitrification and carbon capture is as follows: the flue gas is first cooled and dust-removed, and then enters the slag pile accumulated at the bottom of the granulation bin through the air vents at the bottom of the granulation bin. After reacting with the slag pile, it continues to flow upward, forming convection with the falling fine particles, and finally flows into the exhaust gas treatment device from the side or top of the granulation bin.

7. The process for coupling metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture according to claim 1, characterized in that: The flue gas volume processed per kilogram of slag particles is 5-7.5Nm 3 / h.

8. The process for coupling metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture according to claim 1, characterized in that: The tail gas treatment includes using a cyclone dust collector for primary dust removal and a bag dust collector for secondary dust removal.

9. A system for coupling metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture, characterized in that: It includes a metallurgical slag granulating device, a flue gas conveying device and an exhaust gas treatment device, among which, The metallurgical slag granulation device includes a granulation bin and a slag ladle arranged above the granulation bin. The bottom of the slag ladle is provided with a port for the metallurgical slag to flow out. The port extends into the granulation bin and extends to the vicinity of the jet nozzle. The jet nozzle is connected to an external pressure pump through a pipeline. The smoke conveying device includes an air inlet, a gas pipeline connecting the air inlet with the air vent at the bottom of the granulating bin, and a gas valve arranged at the air inlet end of the gas pipeline; The exhaust gas post-processing device includes a cyclone dust collector connected to the top or side of the granulation bin, a bag dust collector connected to the exhaust port of the cyclone dust collector, and an exhaust gas outlet connected to the exhaust port of the bag dust collector.

10. The system for coupling metallurgical slag granulation with metallurgical flue gas desulfurization, denitrification and carbon capture according to claim 9, characterized in that: The bottom of the granulation bin is also provided with air holes for flue gas input and a funnel for slag particles to be discharged; the granulation bin is a closed granulation bin; the metallurgical slag granulation device, the flue gas conveying device and the tail gas treatment device are combined to obtain a metallurgical slag granulation and metallurgical flue gas desulfurization, denitrification and carbon capture coupling system, which is a closed system in which the internal gas is fully isolated from the external environment.

Images