Method for preparing unburned coal powder in blast furnace tuyere rotation zone

Abstract

The application provides a preparation method of unburned coal powder in a blast furnace tuyere rotation area, and relates to the technical field of blast furnace ironmaking coal injection. The method comprises the following steps: converting actual working condition parameters of blast furnace coal injection into experimental parameters of a blast furnace coal injection simulation experiment device; performing blast furnace coal injection experiments on the experimental device according to the obtained experimental parameters; and collecting unburned coal powder in a cyclone separator after the blast furnace coal injection experiments are completed. Through the above method, the oxygen-carbon atom ratio under the actual working condition can be determined through theoretical calculation, and the coal injection amount under the experimental condition can be determined according to the oxygen-carbon atom ratio. Meanwhile, the volume fraction of nitrogen and oxygen in the compressed gas used under the experimental condition is determined according to the analysis and calculation of the carrier gas injection condition and the oxygen enrichment rate under the actual working condition, so that the unburned coal powder close to the composition of the unburned coal powder actually produced by the blast furnace can be prepared in a simple and efficient manner, thereby improving the accuracy of subsequent scientific research and scientific experiments.

Description

Technical Field

[0001] This invention relates to the field of pulverized coal injection technology in blast furnace ironmaking, and particularly to a method for preparing unburned pulverized coal in the tuyeres of a blast furnace. Background Technology

[0002] Pulverized coal injection into blast furnaces is currently a major means of saving coke and reducing costs in the steel industry, and it is of great significance to actual production. Major steel companies all hope to save coke by increasing the coal-to-coal ratio. However, with the increase in pulverized coal injection, the amount of unburned pulverized coal in the blast furnace also increases. Previous research shows that unburned pulverized coal, regardless of its distribution area in the blast furnace, will worsen the permeability of the burden. Although it remains in the furnace, it does not play its due role and instead leads to an increase in the coke ratio, thus offsetting some of the coke-saving effect brought about by the effective utilization of pulverized coal already burned in the swirl zone.

[0003] The impact of unburned pulverized coal on blast furnaces has been a subject of ongoing research. How to prepare unburned pulverized coal that meets actual operating conditions is crucial for scientifically studying its effects on blast furnaces. However, directly obtaining unburned pulverized coal for blast furnaces is difficult, and in practice, it is usually necessary to prepare it in-house. Currently, most laboratory-prepared unburned pulverized coal uses the dry distillation method. For example, patent CN108929926A provides a method for testing the softening properties of blast furnace burdens. The method for preparing unburned pulverized coal in this patent includes: loading pulverized coal into a stainless steel container and placing it in a muffle furnace; controlling the temperature of the muffle furnace at 1125-1175℃; dry distilling the pulverized coal under a N2 atmosphere for 9-11 hours to remove volatiles; finely grinding the dry-distilled pulverized coal in a ball mill for 0.8-1.2 hours; and sieving to produce unburned pulverized coal. However, this method is time-consuming, and the experimental conditions differ significantly from the actual operating conditions of a blast furnace.

[0004] Patent CN102539621A discloses a method and apparatus for detecting the combustion rate of pulverized coal. This patent designs an apparatus including a hot blast stove, a pulverized coal injection bottle, a combustion furnace, an N2 gas source, a three-way ash collection trough, an air collection bag, and a dust collector. After preparing a coal sample and continuous pulverization, unburned pulverized coal is collected from the bag filter and the three-way ash collection trough. While this method can simulate the pulverized coal injection process to some extent, the equipment is inconvenient to operate, and the experimental conditions differ significantly from the actual operating conditions of a blast furnace. This results in discrepancies between the obtained unburned pulverized coal and the actual unburned pulverized coal from a blast furnace, thus affecting the accuracy of subsequent scientific research based on this unburned pulverized coal.

[0005] In view of this, it is necessary to design an improved method for preparing unburned pulverized coal in the blast furnace tuyeres swirling zone to solve the above problems. Summary of the Invention

[0006] To address the shortcomings of the existing technology, the present invention aims to provide a method for preparing unburned pulverized coal in the tuyeres of a blast furnace. Based on a blast furnace pulverized coal injection simulation experimental device, the actual operating conditions of pulverized coal injection in the blast furnace are transformed into experimental parameters in the blast furnace pulverized coal injection simulation experimental device. By simulating the actual combustion state of pulverized coal injection in the blast furnace, the prepared unburned pulverized coal is made to have a composition close to that of the unburned pulverized coal actually produced in the blast furnace, thereby improving the accuracy of subsequent scientific research and scientific experiments.

[0007] To achieve the above objectives, the present invention provides a method for preparing unburned pulverized coal in the tuyeres of a blast furnace, comprising the following steps:

[0008] S1. Convert the actual operating parameters of pulverized coal injection in blast furnace into the experimental parameters of blast furnace pulverized coal injection simulation experimental equipment.

[0009] The experimental equipment includes a combustion furnace and a compressed gas supply assembly. The compressed gas supply assembly is connected to the input ends of the high-pressure section and the low-pressure section, respectively. The output ends of the high-pressure section and the low-pressure section are connected to the input end of the combustion furnace, respectively. A compressed gas preheating furnace is provided in the low-pressure section, a pulverized coal charging port is provided in the high-pressure section, and the output end of the combustion furnace is connected to a cyclone separator.

[0010] S2. According to the experimental parameters obtained in step S1, operate the experimental equipment to conduct a blast furnace pulverized coal injection experiment.

[0011] S3. After the blast furnace pulverized coal injection experiment is completed, collect the unburned pulverized coal in the cyclone separator.

[0012] As a further improvement of the present invention, in step S1, the actual operating parameters include coal ratio, oxygen enrichment rate, blast volume, pulverized coal carrier gas volume, pig iron production, number of tuyeres, pulverized coal carbon content, hot air temperature and tuyere temperature.

[0013] As a further improvement of the present invention, in step S1, the experimental parameters include the amount of pulverized coal injected, the volume fraction of oxygen in the compressed gas, the volume fraction of nitrogen in the compressed gas, the temperature of the compressed gas preheating furnace, and the temperature of the combustion furnace.

[0014] As a further improvement of the present invention, in step S1, the method for converting the actual operating parameters of pulverized coal injection in a blast furnace into experimental parameters of a blast furnace pulverized coal injection simulation experimental device includes:

[0015] The oxygen-carbon atomic ratio is calculated based on the actual working conditions, and then the amount of pulverized coal injected in the experimental parameters is calculated based on the oxygen-carbon atomic ratio.

[0016] Calculate the oxygen volume fraction and nitrogen integral in the experimental parameters based on the actual operating conditions.

[0017] As a further improvement of the present invention, the oxygen-to-carbon atomic ratio is calculated according to the following formula:

[0018]

[0019] In the formula, A O / C The ratio of oxygen to carbon atoms, n O-con Molar amount of oxygen atoms per vent, mol / s; n C-con The molar amount of carbon atoms per vent, in mol / s; D Oxygen For single-outlet oxygen enrichment, m 3 / s;D PC The coal injection rate at a single air inlet is kg / s; m C-coal The carbon content of pulverized coal is fixed at %.

[0020] As a further improvement of the present invention, the oxygen volume fraction and nitrogen gas integral are calculated according to the following formula:

[0021]

[0022]

[0023] In the formula, The volume fraction of oxygen in the compressed gas, expressed as %. D represents the volume fraction of nitrogen in the compressed gas, expressed as a percentage. Oxygen For single-outlet oxygen enrichment, m 3 / s; For single-nozzle injection of carrier air, m 3 / s; Oxygen enrichment rate, %.

[0024] As a further improvement of the present invention, the amount of pulverized coal injected is determined based on the molar amount of oxygen and the oxygen-to-carbon atomic ratio under experimental conditions, and the calculation formula is as follows:

[0025]

[0026]

[0027]

[0028] In the formula, M coal-exp The amount of pulverized coal injected is expressed in kg; n C-exp n represents the molar amount of carbon under experimental conditions, in mol / s. O-exp The molar amount of oxygen under experimental conditions, in mol / s; The volume of oxygen in the experiment, m 3 V hw-fixed The volume of the experimental hot air is m. 3 .

[0029] As a further improvement of the present invention, in step S2, the step of operating the experimental equipment to conduct a blast furnace pulverized coal injection experiment includes:

[0030] The compressed gas preheating furnace and the combustion furnace are heated to a predetermined temperature; the temperature of the compressed gas preheating furnace is determined according to the hot air temperature in the actual operating parameters, and the temperature of the combustion furnace is determined according to the air outlet temperature in the actual operating parameters.

[0031] Weigh out a predetermined amount of pulverized coal and add it into the pulverized coal charging port;

[0032] Turn on the compressed gas supply assembly to introduce compressed gas into the high-pressure section and the low-pressure section.

[0033] As a further improvement of the present invention, in the experimental equipment, the pressure of the high-pressure section is 0.3 to 0.5 MPa.

[0034] As a further improvement of the present invention, in the experimental equipment, the pressure of the low-pressure section is 0.15 to 0.25 MPa.

[0035] The beneficial effects of this invention are:

[0036] 1. The method for preparing unburned pulverized coal in the blast furnace tuyeres provided by the present invention is based on a blast furnace pulverized coal injection simulation experimental device. By converting the actual operating conditions of pulverized coal injection in the blast furnace into experimental parameters in the blast furnace pulverized coal injection simulation experimental device, the actual combustion state of pulverized coal injection in the blast furnace is simulated, so that the composition of the prepared unburned pulverized coal is close to that of the unburned pulverized coal actually produced in the blast furnace, so as to improve the accuracy of subsequent scientific research and scientific experiments.

[0037] 2. The method for preparing unburned pulverized coal in the blast furnace tuyeres provided by this invention, when converting the actual operating conditions of pulverized coal injection in a blast furnace into experimental parameters in a blast furnace pulverized coal injection simulation experimental device, firstly, uses the oxygen-to-carbon atomic ratio as the conversion standard, and determines the oxygen-to-carbon atomic ratio under actual operating conditions through theoretical calculation, and then determines the pulverized coal injection rate under experimental conditions based on this oxygen-to-carbon atomic ratio; secondly, by analyzing and calculating the carrier gas injection situation and oxygen enrichment rate under actual operating conditions, the volume fractions of nitrogen and oxygen in the compressed gas used under experimental conditions are determined. Through the synergistic effect of the above two aspects, this invention can simulate the pulverized coal combustion state under actual blast furnace operating conditions in a simple and efficient manner, without the need for complex equipment, with a relatively simple control method, and the composition of the unburned pulverized coal obtained is close to that of unburned pulverized coal under actual blast furnace operating conditions, which has important research significance. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the blast furnace pulverized coal injection simulation experimental equipment used in Example 1.

[0039] illustrate:

[0040] 1. Compressed gas storage tank; 2. Inlet valve; 3. Pressure reducing valve; 4. Low-pressure inlet valve; 5. First check valve; 6. Pressure relief valve; 7. Compressed gas preheating furnace; 8. High-pressure inlet valve; 9. Second check valve; 10. High-pressure gas chamber; 11. High-pressure detection device; 12. High-pressure outlet valve; 13. Third check valve; 14. Pulverized coal charging port; 15. Combustion furnace; 16. Low-pressure outlet valve; 17. Cyclone separator; 18. Gas-slag filter; 19. Vacuum pressure gauge; 20. Vent valve; 21. Outlet valve; 22. Gas analyzer. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] It should also be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0043] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0044] To achieve the above objectives, the present invention provides a method for preparing unburned pulverized coal in the tuyeres of a blast furnace, comprising the following steps:

[0045] S1. Convert the actual operating parameters of pulverized coal injection in blast furnace into the experimental parameters of blast furnace pulverized coal injection simulation experimental equipment.

[0046] The experimental equipment includes a combustion furnace and a compressed gas supply assembly. The compressed gas supply assembly is connected to the input ends of the high-pressure section and the low-pressure section, respectively. The output ends of the high-pressure section and the low-pressure section are connected to the input end of the combustion furnace, respectively. A compressed gas preheating furnace is provided in the low-pressure section, a pulverized coal charging port is provided in the high-pressure section, and the output end of the combustion furnace is connected to a cyclone separator.

[0047] S2. According to the experimental parameters obtained in step S1, operate the experimental equipment to conduct a blast furnace pulverized coal injection experiment.

[0048] S3. After the blast furnace pulverized coal injection experiment is completed, collect the unburned pulverized coal in the cyclone separator.

[0049] In step S1, the actual operating parameters include coal ratio, oxygen enrichment rate, blast volume, pulverized coal carrier gas volume, pig iron production, number of tuyeres, pulverized coal carbon content, hot air temperature, and tuyere temperature. The experimental parameters include the amount of pulverized coal injected, the volume fraction of oxygen in the compressed gas, the volume fraction of nitrogen in the compressed gas, the temperature of the compressed gas preheating furnace, and the temperature of the combustion furnace. The temperature of the compressed gas preheating furnace is determined based on the hot air temperature in the actual operating parameters, and the temperature of the combustion furnace is determined based on the tuyere temperature in the actual operating parameters.

[0050] Specifically, methods for converting actual operating parameters of pulverized coal injection in a blast furnace into experimental parameters for a blast furnace pulverized coal injection simulation test device include:

[0051] The oxygen-carbon atomic ratio is calculated based on the actual working conditions, and then the amount of pulverized coal injected in the experimental parameters is calculated based on the oxygen-carbon atomic ratio.

[0052] Calculate the oxygen volume fraction and nitrogen integral in the experimental parameters based on the actual operating conditions.

[0053] The oxygen-to-carbon atomic ratio is calculated according to the following formula:

[0054]

[0055] In the formula, A O / C The ratio of oxygen to carbon atoms, n O-con Molar amount of oxygen atoms per vent, mol / s; n C-con The molar amount of carbon atoms per vent, in mol / s; D Oxygen For single-outlet oxygen enrichment, m 3 / s;D PC The coal injection rate at a single air inlet is kg / s; m C-coal The carbon content of pulverized coal is fixed at %.

[0056] The oxygen volume fraction and nitrogen integral are calculated according to the following formula:

[0057]

[0058]

[0059] In the formula, The volume fraction of oxygen in the compressed gas, expressed as %. D represents the volume fraction of nitrogen in the compressed gas, expressed as a percentage. Oxygen For single-outlet oxygen enrichment, m 3 / s; For single-nozzle injection of carrier air, m 3 / s; Oxygen enrichment rate, %.

[0060] The amount of pulverized coal injected is determined based on the molar amount of oxygen and the oxygen-to-carbon atomic ratio under experimental conditions, and the calculation formula is as follows:

[0061]

[0062]

[0063]

[0064] In the formula, M coal-exp The amount of pulverized coal injected is expressed in kg; n C-exp n represents the molar amount of carbon under experimental conditions, in mol / s. O-exp The molar amount of oxygen under experimental conditions, in mol / s; The volume of oxygen in the experiment, m 3 V hw-fixed The volume of the experimental hot air is m. 3 .

[0065] In step S2, the steps of operating the experimental equipment to conduct the blast furnace pulverized coal injection experiment include:

[0066] The compressed gas preheating furnace and the combustion furnace are heated to a predetermined temperature;

[0067] Weigh out a predetermined amount of pulverized coal and add it into the pulverized coal charging port;

[0068] Turn on the compressed gas supply assembly to introduce compressed gas into the high-pressure section and the low-pressure section.

[0069] In the experimental equipment, the pressure in the high-pressure section is 0.3 to 0.5 MPa.

[0070] In the experimental equipment, the pressure in the low-pressure section is 0.15–0.25 MPa.

[0071] The preparation method of unburned pulverized coal in the blast furnace tuyeres swirling zone provided by the present invention will be described in detail below with reference to specific embodiments.

[0072] Example 1

[0073] This embodiment provides a method for preparing unburned pulverized coal in the tuyeres of a blast furnace, using methods such as... Figure 1 The blast furnace pulverized coal injection simulation experimental equipment shown was used for the experiment.

[0074] The blast furnace pulverized coal injection simulation experimental equipment includes a combustion furnace 15 and a compressed gas supply assembly, wherein the compressed gas supply assembly includes a compressed gas storage tank 1 and an inlet valve 2. The compressed gas storage tank 1 is connected to the input ends of the high-pressure section and the low-pressure section respectively through the inlet valve 2. The low-pressure section is equipped with a pressure reducing valve 3, a low-pressure inlet valve 4, a first one-way valve 5, a pressure relief valve 6, and a compressed gas preheating furnace 7 in sequence from the input end to the output end. The high-pressure section is equipped with a high-pressure inlet valve 8, a second one-way valve 9, a high-pressure gas chamber 10, a high-pressure pressure detection device 11, a high-pressure outlet valve 12, a third one-way valve 13, and a pulverized coal charging port 14 in sequence from the input end to the output end. The output ends of the high-pressure section and the low-pressure section are respectively connected to the input end of the combustion furnace 15. The output end of the combustion furnace 15 is sequentially connected to the low-pressure exhaust valve 16, the cyclone separator 17, the gas slag filter 18, the vacuum pressure gauge 19, the exhaust valve 21, and the gas analyzer 22. A vent valve 20 is also provided between the exhaust valve 21 and the vacuum pressure gauge 19.

[0075] Based on the above experimental equipment, the method for preparing unburned pulverized coal in the blast furnace tuyeres swirling zone provided in this embodiment specifically includes the following steps:

[0076] S1. Convert the actual operating parameters of pulverized coal injection in the blast furnace into experimental parameters of the blast furnace pulverized coal injection simulation test equipment.

[0077] In this embodiment, the actual operating parameters of pulverized coal injection in the blast furnace and the composition analysis of the coal sample used in the simulation experiment are shown in Table 1 and Table 2, respectively.

[0078] Table 1 Actual operating parameters of pulverized coal injection in blast furnace

[0079]

[0080] Table 2. Coal samples used in the simulation experiment.

[0081]

[0082] The oxygen-to-carbon atomic ratio is calculated based on the actual operating parameters, and then the amount of pulverized coal injected in the experimental parameters is calculated based on the oxygen-to-carbon atomic ratio. The specific method is as follows:

[0083] The pulverized coal injection rate (kg / s) per tuyer is calculated based on the coal ratio and pig iron production, while the oxygen enrichment rate (m³) per tuyer is calculated based on the blast volume and oxygen volume fraction. 3 The oxygen molar amount at a single tuyere is determined by the oxygen enrichment rate of the single tuyere injection, and the carbon molar amount at a single tuyere is determined by the coal injection rate, thus obtaining the oxygen-carbon ratio. The specific results are as follows:

[0084]

[0085]

[0086]

[0087] The oxygen volume fraction is calculated based on the oxygen enrichment rate of a single air outlet, the carrier gas volume of a single air outlet, and the oxygen enrichment rate. The nitrogen gas fraction is calculated using the difference method. The specific calculation process is as follows:

[0088]

[0089]

[0090]

[0091] The experimental oxygen volume and experimental hot air volume are calculated based on the pipeline volume in the experimental equipment. In the experimental equipment provided in this embodiment, the experimental oxygen volume is... Experimental hot air volume V hw-fixed =2.46298×10 -4 m 3 Based on the carbon-oxygen atomic ratio calculated in the above process, the amount of pulverized coal injected during the experiment can be calculated. The specific calculation process is as follows:

[0092]

[0093]

[0094]

[0095] S2. According to the experimental parameters obtained in step S1, operate the experimental equipment to conduct a blast furnace pulverized coal injection experiment. The specific operation method is as follows:

[0096] The compressed gas preheating furnace 7 is heated to 1100°C, and the combustion furnace 15 is heated to 1500°C;

[0097] Weigh 0.0878g of coal powder according to the calculation results in step S1 and add it into the coal powder loading port 14;

[0098] Prepare the corresponding compressed gas according to the volume fractions of oxygen and nitrogen in step S1, store it in the compressed gas supply assembly, and then open the compressed gas supply assembly to introduce compressed gas into the high-pressure section and the low-pressure section. The pressure of the high-pressure section is 0.4 MPa and the pressure of the low-pressure section is 0.2 MPa.

[0099] S3. After the reaction lasts for 110 seconds and the blast furnace pulverized coal injection experiment is completed, collect the unburned pulverized coal in the cyclone separator.

[0100] The composition of the unburned coal powder obtained in this embodiment and the unburned coal powder sampled from the blast furnace tuyeres were analyzed, and the results are shown in Table 3.

[0101] Table 3 Comparison of unburned pulverized coal prepared in Example 1 with unburned pulverized coal sampled from the blast furnace tuyeres.

[0102]

[0103] As can be seen from Table 3, the composition of the unburned coal powder prepared in this embodiment is similar to that of the unburned coal powder actually produced in the blast furnace, which can ensure the accuracy and scientific nature of subsequent experimental research.

[0104] In summary, this invention provides a method for preparing unburned pulverized coal in the blast furnace tuyeres, relating to the field of pulverized coal injection technology in blast furnace ironmaking. The method includes: converting the actual operating parameters of pulverized coal injection in a blast furnace into experimental parameters for a blast furnace pulverized coal injection simulation experimental device; conducting a blast furnace pulverized coal injection experiment according to the obtained experimental parameters; and collecting the unburned pulverized coal from the cyclone separator after the blast furnace pulverized coal injection experiment is completed. Through the above method, this invention can theoretically calculate the oxygen-to-carbon atomic ratio under actual operating conditions, and then determine the pulverized coal injection rate under experimental conditions based on this oxygen-to-carbon atomic ratio; simultaneously, based on the analysis and calculation of the carrier gas injection situation and oxygen enrichment rate under actual operating conditions, the volume fractions of nitrogen and oxygen in the compressed gas used under experimental conditions are determined, thereby preparing unburned pulverized coal with a composition close to that actually produced in a blast furnace in a simple and efficient manner, thus improving the accuracy of subsequent scientific research and experimental work.

[0105] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing unburned pulverized coal in the tuyeres of a blast furnace, characterized in that, The steps include the following: S1. Convert the actual operating parameters of pulverized coal injection in blast furnace into the experimental parameters of blast furnace pulverized coal injection simulation experimental equipment. The experimental equipment includes a combustion furnace and a compressed gas supply assembly. The compressed gas supply assembly is connected to the input ends of the high-pressure section and the low-pressure section, respectively. The output ends of the high-pressure section and the low-pressure section are connected to the input end of the combustion furnace, respectively. A compressed gas preheating furnace is provided in the low-pressure section, a pulverized coal charging port is provided in the high-pressure section, and the output end of the combustion furnace is connected to a cyclone separator. S2. According to the experimental parameters obtained in step S1, operate the experimental equipment to conduct a blast furnace pulverized coal injection experiment. S3. After the blast furnace pulverized coal injection experiment is completed, collect the unburned pulverized coal in the cyclone separator; In step S1, the experimental parameters include the amount of pulverized coal injected, the volume fraction of oxygen in the compressed gas, the volume fraction of nitrogen in the compressed gas, the temperature of the compressed gas preheating furnace, and the temperature of the combustion furnace. In step S1, the method for converting the actual operating parameters of pulverized coal injection in a blast furnace into the experimental parameters of a blast furnace pulverized coal injection simulation experimental device includes: The oxygen-carbon atomic ratio is calculated based on the actual working conditions, and then the amount of pulverized coal injected in the experimental parameters is calculated based on the oxygen-carbon atomic ratio. Calculate the oxygen volume fraction and nitrogen integral in the experimental parameters based on the actual operating conditions.

2. The method for preparing unburned pulverized coal in the blast furnace tuyeres swirling zone according to claim 1, characterized in that: In step S1, the actual operating parameters include coal ratio, oxygen enrichment rate, blast volume, pulverized coal carrier gas volume, pig iron production, number of tuyeres, pulverized coal carbon content, hot air temperature, and tuyere temperature.

3. The method for preparing unburned pulverized coal in the blast furnace tuyeres swirling zone according to claim 1, characterized in that: The oxygen-to-carbon atomic ratio is calculated according to the following formula: In the formula, The ratio of oxygen to carbon atoms. The molar amount of oxygen atoms at a single air outlet, in mol; The molar amount of carbon atoms per air outlet, in mol; For single-outlet oxygen enrichment, m 3 / s; The coal injection rate at a single air inlet is kg / s; The carbon content of pulverized coal is fixed at %.

4. The method for preparing unburned pulverized coal in the blast furnace tuyeres swirling zone according to claim 3, characterized in that: The oxygen volume fraction and nitrogen integral are calculated according to the following formula: In the formula, The volume fraction of oxygen in the compressed gas, % The volume fraction of nitrogen in the compressed gas, % For single-outlet oxygen enrichment, m 3 / s; For single-nozzle injection of carrier air, m 3 / s; Oxygen enrichment rate, %.

5. The method for preparing unburned pulverized coal in the blast furnace tuyeres swirling zone according to claim 4, characterized in that: The amount of pulverized coal injected is determined based on the molar amount of oxygen and the oxygen-to-carbon atomic ratio under experimental conditions, and the calculation formula is as follows: In the formula, The amount of pulverized coal injected is in kg; The molar amount of carbon under experimental conditions, in mol; The molar amount of oxygen under experimental conditions, expressed in mol. The volume of oxygen in the experiment, m 3 ; The volume of the experimental hot air is m. 3 .

6. The method for preparing unburned pulverized coal in the blast furnace tuyeres swirling zone according to claim 1, characterized in that: In step S2, the steps of operating the experimental equipment to conduct the blast furnace pulverized coal injection experiment include: The compressed gas preheating furnace and the combustion furnace are heated to a predetermined temperature; the temperature of the compressed gas preheating furnace is determined according to the hot air temperature in the actual operating parameters, and the temperature of the combustion furnace is determined according to the air outlet temperature in the actual operating parameters. Weigh out a predetermined amount of pulverized coal and add it into the pulverized coal charging port; Turn on the compressed gas supply assembly to introduce compressed gas into the high-pressure section and the low-pressure section.

7. The method for preparing unburned pulverized coal in the blast furnace tuyeres swirling zone according to claim 1, characterized in that: In the experimental equipment, the pressure in the high-pressure section is 0.3~0.5MPa.

8. The method for preparing unburned pulverized coal in the blast furnace tuyeres swirling zone according to claim 1, characterized in that: In the experimental equipment, the pressure in the low-pressure section is 0.15~0.25MPa.

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