Method for increasing coal ratio of blast furnace

Abstract

The invention relates to the technical field of blast furnace ironmaking, in particular to a method for increasing the blast furnace coal ratio. According to the technical scheme, the method for increasing the coal ratio of the blast furnace comprises the following steps: (S1) stabilizing and strengthening the pressure of an injection system: installing a compressed air buffer tank at the front end of a coal injection main pipeline in parallel, and stabilizing the pressure in the tank through a pressure controller; meanwhile, a nitrogen flow-coal injection quantity closed-loop control model is established in a nitrogen branch pipe, and the nitrogen flow is dynamically adjusted; (S2) multi-tuyere cooperative injection: monitoring the pulverized coal flow at each tuyere branch pipe in real time, and realizing flow balance by adjusting a distributor valve; (S3) high air temperature control: the internal structure of the hot blast stove is replaced to reduce resistance, and the vault temperature is increased by adopting oxygen-enriched combustion; and closing the air mixing valve and starting a temperature compensation algorithm to maintain high air temperature. Initial preheating and deep oxygen supply in a combustion core area of the graded oxygen enrichment mechanism when the pulverized coal enters the hearth are achieved, and nearly complete combustion of the pulverized coal is achieved with the assistance of a rotational flow mixing technology.

Description

Technical Field

[0001] The present invention relates to the technical field of blast furnace ironmaking, and in particular to a method for improving the coal ratio of a blast furnace. Background Art

[0002] The blast furnace coal ratio refers to the ratio of the amount of pulverized coal injected during the blast furnace smelting process to the pig iron output, with the unit of kg / t. It is the core indicator for measuring blast furnace smelting efficiency.

[0003] In the prior art, the pressure of the pulverized coal injection system fluctuates frequently, resulting in serious uneven distribution of pulverized coal at each tuyere, blockage of some tuyere and insufficient coal supply at other tuyere.

[0004] The traditional fixed oxygen enrichment method cannot adapt to the dynamic needs of coal powder combustion. A large amount of unburned coal powder enters the material column, reducing the permeability, and is discharged with the slag, causing waste of resources; static coal blending only mechanically controls the upper limit of volatile matter, and it is easy to exceed the critical point of explosion when the temperature and pressure in the furnace fluctuate, and lacks a safety protection mechanism for working condition linkage; it relies on manual experience to adjust parameters, and the feedback of key signals such as changes in coal gas composition and coal powder combustion status is slow, which restricts the room for improvement of coal ratio. Summary of the Invention

[0005] The present invention proposes a method for improving the blast furnace coal ratio, which solves the problem that the existing static control method cannot simultaneously solve the problems of uneven injection distribution, insufficient coal powder combustion and safety risks under dynamic working conditions, resulting in limited improvement of the blast furnace coal ratio.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A method for increasing the blast furnace coal ratio comprises the following steps:

[0008] (S1) Strengthening the pressure stabilization of the injection system: A compressed air buffer tank is installed in parallel at the front end of the coal injection main pipeline, and the pressure in the tank is stabilized by a pressure controller. At the same time, a nitrogen flow-coal injection amount closed-loop control model is established in the nitrogen branch pipe to dynamically adjust the nitrogen flow;

[0009] (S2) Multi-tuyere coordinated injection: The pulverized coal flow rate is monitored in real time at each tuyere branch pipe, and the flow rate is balanced by adjusting the distributor valve;

[0010] (S3) High air temperature control: Replace the internal structure of the hot air furnace to reduce resistance, use oxygen-enriched combustion to increase the dome temperature; close the air mixing valve and enable the temperature compensation algorithm to maintain high air temperature;

[0011] (S4) Optimization of safe coal blending: Construct a cost-effectiveness function for pulverized coal and calculate the safety factor of volatile matter, select coals with high cost-effectiveness and mix them in proportion, and control the mixed volatile matter to be below the explosion threshold;

[0012] (S5) Gradual oxygen enrichment supply: low-pressure oxygen is injected into the cold air duct and high-pressure oxygen is injected above the vortex area of the tuyere to control the total oxygen enrichment rate and form an oxygen potential gradient;

[0013] (S6) Combustion state feedback adjustment: Based on the gas composition analysis and unburned coal powder detection results, the oxygen enrichment amount and coal injection amount are dynamically adjusted.

[0014] Furthermore, the closed-loop control model of step (S1) adopts an exponential function relationship:

[0015]

[0016] where Q N is the nitrogen flow rate, Q C is the real-time coal injection amount, K is the proportional coefficient, and α is the coal powder fluidity index; dynamic correction mechanism: pipeline pressure difference data is collected during each production cycle. When the pressure difference fluctuation exceeds the set threshold, the α value is refitted using the least squares method;

[0017] Anti-blocking protection: When Q N / Q C When the ratio is lower than the safety lower limit, the nitrogen boost program is automatically triggered.

[0018] Furthermore, the temperature compensation algorithm of step (S3) includes dual-module collaboration:

[0019] (a) Air temperature prediction module: An ARIMA prediction model is constructed based on the time series analysis method. The input variables include the temperature change rate of the hot blast furnace dome, the oxygen content of the exhaust gas, and the duration of the air supply cycle.

[0020] (b) Compensation execution module: When the predicted wind temperature is lower than the critical value, three-way parallel compensation is started:

[0021] Turn on the standby hot air furnace to supply air in parallel;

[0022] Activate the electric auxiliary heating device of the hot air duct;

[0023] Increase the calorific value of coal gas during the hot blast furnace firing period.

[0024] Furthermore, the explosion threshold dynamic calculation model of step (S4) is:

[0025] V lim =β0+β1PO2-β2T g

[0026] Where V lim is the dynamic explosion threshold, β0, β1, and β2 are material characteristic coefficients, which are calibrated by coal powder explosion test experiments, PO2 is the oxygen enrichment pressure, and T g is the gas temperature;

[0027] Safety margin control: Set the upper limit of mixed volatile matter to meet the following requirements:

[0028]

[0029] Where V max is the upper limit of mixed volatile matter, γ is the safety factor, ranging from 0.5 to 1.0;

[0030] Control the volatile matter of the mixed coal powder to meet V mix ≤V max .

[0031] Furthermore, the swirl guide plate structure design in step (S5) is as follows:

[0032] The guide plate inclination angle can be adjusted from 30° to 50°, and the surface is covered with a tungsten carbide wear-resistant layer;

[0033] The oxygen flow channel is distributed in the form of an Archimedean spiral, and the pitch changes with the pressure gradient;

[0034] The guide plate substrate is provided with a microporous nitriding cooling channel.

[0035] Furthermore, the slag phase analysis method in step (S6) specifically includes:

[0036] (a) Slag sample preparation: The slag at the slag-iron interface was rapidly cooled and solidified, and then cut and polished to a mirror surface;

[0037] (b) Image analysis: Scan the field of view under a 200x microscope to identify the outline of the iron bead;

[0038] (c) Calculation of unburned rate: Calculate the area ratio of iron balls with diameters greater than 50 μm and convert the unburned rate of pulverized coal into the following formula:

[0039]

[0040] Furthermore, the cost performance function construction method of step (S4) is:

[0041]

[0042] Where λ1+λ2+λ3=1, and λ3≥0.4;

[0043] Coal type screening rules: give priority to the coal types with the top three η values, and allocate the mixing ratio according to the difference in activation energy of the elementary reactions.

[0044] Furthermore, the hierarchical oxygen supply strategy of step (S5) is:

[0045] Low-pressure oxygen (0.05-0.15 MPa) is injected into the cold air main through an annular distributor, with an oxygen concentration gradient of ≤5% / m;

[0046] High-pressure oxygen (2.0-3.5 MPa) is accelerated to supersonic speed through the Laval nozzle and injected tangentially at a distance of 2.0±0.3 m from the tuyere.

[0047] Furthermore, the flow balance control method of step (S2) is:

[0048] (a) Deviation detection: Take 32 air outlets as monitoring units and calculate the flow standard deviation σ:

[0049]

[0050] (b) Adjustment strategy: When σ>8%, open the taper valve for graded adjustment:

[0051] For over-flow tuyere, close it step by step (each step ≤ 2% opening)

[0052] The underflow tuyere is opened in a pulsed manner using high-frequency short pulses.

[0053] Furthermore, the feedback adjustment logic of step (S6) is:

[0054] (I) When CO / CO2<0.25, ΔO2=K1e -t / τ The function increases the oxygen enrichment, where K1 is the base increment and τ is the furnace capacity time constant;

[0055] (II) When the unburned rate is greater than 5%, a two-level response is initiated:

[0056] Primary response: coal injection rate decreases at a slope of -0.5t / (h·min)

[0057] Secondary response: When the unburned rate is >8%, inject the combustion-supporting catalyst.

[0058] The positive effects of the present invention are as follows: the compressed air buffer tank eliminates pressure pulsation, and cooperates with nitrogen closed-loop control to achieve highly balanced pulverized coal flow in the tuyere; the graded oxygen enrichment mechanism preheats the pulverized coal at the initial stage of entering the furnace and deeply supplies oxygen to the core combustion area, assisted by swirl mixing technology to achieve near-complete combustion of the pulverized coal; the dynamic explosion threshold model calculates the safety margin in real time, so that the volatile matter of the blended coal is always lower than the critical value of the operating condition; the dual feedback of slag phase analysis and gas composition detection drives the self-optimization of parameters, forming a "perception-decision-execution" closed loop of pulverized coal injection in the blast furnace; the coke substitution rate is significantly improved, the furnace condition stability is enhanced, and the smelting cost is structurally reduced. DETAILED DESCRIPTION

[0059] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0060] A method for increasing the blast furnace coal ratio comprises the following steps:

[0061] (S1) Strengthening the pressure stabilization of the injection system: A compressed air buffer tank is installed in parallel at the front end of the coal injection main pipeline, and the pressure in the tank is stabilized by a pressure controller. At the same time, a nitrogen flow-coal injection amount closed-loop control model is established in the nitrogen branch pipe to dynamically adjust the nitrogen flow;

[0062] (S2) Multi-tuyere coordinated injection: The pulverized coal flow rate is monitored in real time at each tuyere branch pipe, and the flow rate is balanced by adjusting the distributor valve;

[0063] (S3) High air temperature control: Replace the internal structure of the hot air furnace to reduce resistance, use oxygen-enriched combustion to increase the dome temperature; close the air mixing valve and enable the temperature compensation algorithm to maintain high air temperature;

[0064] (S4) Optimization of safe coal blending: Construct a cost-effectiveness function for pulverized coal and calculate the safety factor of volatile matter, select coals with high cost-effectiveness and mix them in proportion, and control the mixed volatile matter to be below the explosion threshold;

[0065] (S5) Gradual oxygen enrichment supply: low-pressure oxygen is injected into the cold air duct and high-pressure oxygen is injected above the vortex area of the tuyere to control the total oxygen enrichment rate and form an oxygen potential gradient;

[0066] (S6) Combustion state feedback adjustment: Based on the gas composition analysis and unburned coal powder detection results, the oxygen enrichment amount and coal injection amount are dynamically adjusted.

[0067] The closed-loop control model of step (S1) adopts an exponential function relationship:

[0068]

[0069] where Q N is the nitrogen flow rate, Q C is the real-time coal injection amount, K is the proportional coefficient, and α is the coal powder fluidity index; dynamic correction mechanism: pipeline pressure difference data is collected during each production cycle. When the pressure difference fluctuation exceeds the set threshold, the α value is refitted using the least squares method;

[0070] Anti-blocking protection: When Q N / Q C When the ratio is lower than the safety lower limit, the nitrogen boost program is automatically triggered.

[0071] The temperature compensation algorithm in step (S3) includes two modules working together:

[0072] (a) Air temperature prediction module: An ARIMA prediction model is constructed based on the time series analysis method. The input variables include the temperature change rate of the hot blast furnace dome, the oxygen content of the exhaust gas, and the duration of the air supply cycle.

[0073] (b) Compensation execution module: When the predicted wind temperature is lower than the critical value, three-way parallel compensation is started:

[0074] Turn on the standby hot air furnace to supply air in parallel;

[0075] Activate the electric auxiliary heating device of the hot air duct;

[0076] Increase the calorific value of coal gas during the hot blast furnace firing period.

[0077] The explosion threshold dynamic calculation model of step (S4):

[0078] V lim =β0+β1PO2-β2T g

[0079] Where V lim is the dynamic explosion threshold, β0, β1, and β2 are material characteristic coefficients, which are calibrated by coal powder explosion test experiments, PO2 is the oxygen enrichment pressure, and T g is the gas temperature;

[0080] Safety margin control: Set the upper limit of mixed volatile matter to meet the following requirements:

[0081]

[0082] Where V max is the upper limit of mixed volatile matter, γ is the safety factor, ranging from 0.5 to 1.0;

[0083] Control the volatile matter of the mixed coal powder to meet V mix ≤V max .

[0084] The swirl guide plate structure design in step (S5):

[0085] The guide plate inclination angle can be adjusted from 30° to 50°, and the surface is covered with a tungsten carbide wear-resistant layer;

[0086] The oxygen flow channel is distributed in the form of an Archimedean spiral, and the pitch changes with the pressure gradient;

[0087] The guide plate substrate is provided with a microporous nitriding cooling channel.

[0088] The slag phase analysis method of step (S6) specifically includes:

[0089] (a) Slag sample preparation: The slag at the slag-iron interface was rapidly cooled and solidified, and then cut and polished to a mirror surface;

[0090] (b) Image analysis: Scan the field of view under a 200x microscope to identify the outline of the iron bead;

[0091] (c) Calculation of unburned rate: Calculate the area ratio of iron balls with diameters greater than 50 μm and convert the unburned rate of pulverized coal into the following formula:

[0092]

[0093] Method for constructing the cost-performance function in step (S4):

[0094]

[0095] Where λ1+λ2+λ3=1, and λ3≥0.4;

[0096] Coal type screening rules: give priority to the coal types with the top three η values, and allocate the mixing ratio according to the difference in activation energy of the elementary reactions.

[0097] Step (S5) of the hierarchical oxygen supply strategy:

[0098] Low-pressure oxygen (0.05-0.15 MPa) is injected into the cold air main through an annular distributor, with an oxygen concentration gradient of ≤5% / m;

[0099] High-pressure oxygen (2.0-3.5 MPa) is accelerated to supersonic speed through the Laval nozzle and injected tangentially at a distance of 2.0±0.3 m from the tuyere.

[0100] Flow balancing control method of step (S2):

[0101] (a) Deviation detection: Take 32 air outlets as monitoring units and calculate the flow standard deviation σ:

[0102]

[0103] (b) Adjustment strategy: When σ>8%, open the taper valve for graded adjustment:

[0104] For over-flow tuyere, close it step by step (each step ≤ 2% opening)

[0105] The underflow tuyere is opened in a pulsed manner using high-frequency short pulses.

[0106] Feedback adjustment logic of step (S6):

[0107] (I) When CO / CO2<0.25, ΔO2=K1e -t / τ The function increases the oxygen enrichment, where K1 is the base increment and τ is the furnace capacity time constant;

[0108] (II) When the unburned rate is greater than 5%, a two-level response is initiated:

[0109] Primary response: coal injection rate decreases at a slope of -0.5t / (h·min)

[0110] Secondary response: When the unburned rate is >8%, inject the combustion-supporting catalyst.

[0111] Example 1

[0112] 2500m 3 Blast furnace implementation case:

[0113] 1. Pressure stabilization and strengthening of the injection system: install 20m in parallel at the front end of the coal injection main pipeline 3 The compressed air buffer tank is stabilized at 0.65±0.03MPa through a PID controller. A nitrogen closed-loop control model is established: initial parameters K=38, α=1.18 (set according to the characteristics of bituminous coal). Pipeline pressure difference data is collected every 8 hours. When the fluctuation exceeds 50kPa, the α value is refitted and the safety lower limit is set: Q N / Q C <35Nm 3 / t triggers nitrogen pressure increase to 0.8MPa.

[0114] 2. Multi-inlet coordinated injection:

[0115] E+H 80F flowmeters (±1.5% accuracy) were installed on 32 tuyere branches.

[0116] Real-time calculation of the standard deviation of air outlet flow σ:

[0117] When σ>8%, for overflow air vents: close the valve step by step (2% opening per step, 30 seconds interval); for underflow air vents: implement high-frequency short pulse adjustment (0.1 second pulse, 0.5 second interval).

[0118] 3. High air temperature control

[0119] Replace the checker bricks of the hot blast furnace with 3mm pore honeycomb, use 26% oxygen concentration oxygen-enriched combustion during the firing period, and when the predicted air temperature is <1230℃:

[0120] Start two hot air furnaces in parallel to supply air, turn on the 200kW electric auxiliary heating device, and increase the calorific value of the gas from 1750 to 1850kcal / Nm 3 .

[0121] 4. Optimization of safe coal blending

[0122] The weight settings of the cost-performance function are: λ1 = 0.3 (economy), λ2 = 0.25 (thermal efficiency), and λ3 = 0.45 (safety);

[0123] Explosion threshold parameters: β0 = 26.5, β1 = 0.15, β2 = 0.08 (calibrated according to GB / T13470);

[0124] Actual mix ratio: anthracite 60% + bituminous coal 30% + lignite 10%, control V_mix = 25.8%.

[0125] 5. Graded oxygen enrichment supply:

[0126] Low-pressure oxygen (0.1MPa) is injected into the cold air main through an annular distributor, and high-pressure oxygen (3.0MPa) is accelerated by a Laval nozzle and sprayed tangentially through a 40° swirl guide plate 2.0m away from the air outlet; a 0.5mm tungsten carbide wear-resistant layer is sprayed on the surface of the guide plate.

[0127] 6. Combustion status feedback:

[0128] Analyze the CO / CO2 ratio of the furnace top gas every 15 minutes. When CO / CO2<0.25: increase the oxygen enrichment according to ΔO2=2.5e^(-t / 15).

[0129] Slag sample inspection: Liquid nitrogen quenching → diamond polishing → 200x microscope scanning

[0130] When the unburned rate is greater than 5%, the coal injection rate decreases at a slope of 0.5t / (h·min); when the unburned rate is greater than 8%, nano-Fe2O3 catalyst (0.3kg / t iron) is injected.

[0131] Example 2

[0132] 3200m 3 Blast furnace optimization solution:

[0133] The inclination angle of the swirl guide plate is adjusted to 45°;

[0134] The high-pressure oxygen injection point was changed to 1.8m;

[0135] Safety factor γ=0.6, calculate

[0136] Nitrogen closed-loop model parameters: K = 40, α = 1.22.

[0137] Example 3

[0138] 1. Add slag phase automatic analysis system: online sampling device (sampling every 30 minutes), automatic polishing machine (processing time < 5 minutes), intelligent image recognition software (automatic iron ball statistics).

[0139] 2. Real-time prediction using ARIMA model:

[0140] The weights of input variables were optimized: the vault temperature change rate was 0.7, the exhaust gas oxygen content was 0.2, and the prediction period was shortened to 10 minutes.

[0141] Comparative Example

[0142] The comparative example is the traditional process, specifically a fixed oxygen enrichment rate of 3.0%, static coal blending (volatile matter ≤ 30%), and no wind temperature compensation;

[0143] Results: Coal ratio 150kg / t, unburned rate 11.2%

[0144] Comparison of implementation effects:

[0145] index Example 1 Example 2 Example 3 Comparative Example Coal ratio (kg / t) 185 192 195 150 Coke ratio (kg / t) 298 295 292 350 Air outlet deviation (%) 3.8 3.2 2.9 15.6 Unburned rate (%) 3.2 2.8 2.5 11.2 Wind temperature fluctuation (℃) ±9 ±7 ±5 ±28

[0146] The above-mentioned embodiments are described in a relatively detailed and specific manner, expressing preferred embodiments of the present invention. They are only used to illustrate the technical ideas and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. However, they are not limited to the present invention alone, and the patent scope of the present invention cannot be limited solely by these embodiments. That is, any equivalent changes or modifications made to the spirit disclosed by the present invention, for researchers or technicians in this field, without departing from the structure of the present invention, local improvements within the system and changes and conversions between subsystems, etc., are still within the patent scope of the present invention.

Claims

1. A method for increasing the blast furnace coal ratio, characterized in that: The following steps are involved: (S1) Strengthening the pressure stabilization of the injection system: A compressed air buffer tank is installed in parallel at the front end of the coal injection main pipeline, and the pressure in the tank is stabilized by a pressure controller. At the same time, a nitrogen flow-coal injection amount closed-loop control model is established in the nitrogen branch pipe to dynamically adjust the nitrogen flow; (S2) Multi-tuyere coordinated injection: The pulverized coal flow rate is monitored in real time at each tuyere branch pipe, and the flow rate is balanced by adjusting the distributor valve; (S3) High air temperature control: Replace the internal structure of the hot air furnace to reduce resistance, use oxygen-enriched combustion to increase the dome temperature; close the air mixing valve and enable the temperature compensation algorithm to maintain high air temperature; (S4) Optimization of safe coal blending: Construct a cost-effectiveness function for pulverized coal and calculate the safety factor of volatile matter, select coals with high cost-effectiveness and mix them in proportion, and control the mixed volatile matter to be below the explosion threshold; (S5) Gradual oxygen enrichment supply: low-pressure oxygen is injected into the cold air duct and high-pressure oxygen is injected above the vortex area of the tuyere to control the total oxygen enrichment rate and form an oxygen potential gradient; (S6) Combustion state feedback adjustment: Based on the gas composition analysis and unburned coal powder detection results, the oxygen enrichment amount and coal injection amount are dynamically adjusted.

2. The method for increasing the blast furnace coal ratio according to claim 1, characterized in that: The closed-loop control model of step (S1) adopts an exponential function relationship: where Q N is the nitrogen flow rate, Q C is the real-time coal injection amount, K is the proportional coefficient, and α is the coal powder fluidity index; dynamic correction mechanism: pipeline pressure difference data is collected during each production cycle. When the pressure difference fluctuation exceeds the set threshold, the α value is refitted using the least squares method; Anti-blocking protection: When Q N / Q C When the ratio is lower than the safety lower limit, the nitrogen boost program is automatically triggered.

3. The method for increasing the blast furnace coal ratio according to claim 1, characterized in that: The temperature compensation algorithm in step (S3) includes two modules working together: (a) Air temperature prediction module: An ARIMA prediction model is constructed based on the time series analysis method. The input variables include the temperature change rate of the hot blast furnace dome, the oxygen content of the exhaust gas, and the duration of the air supply cycle. (b) Compensation execution module: When the predicted wind temperature is lower than the critical value, three-way parallel compensation is started: Turn on the standby hot air furnace to supply air in parallel; Activate the electric auxiliary heating device of the hot air duct; Increase the calorific value of coal gas during the hot blast furnace firing period.

4. The method for increasing the blast furnace coal ratio according to claim 1, characterized in that: The explosion threshold dynamic calculation model of step (S4): V lim =β0+β1PO2-β2T g Where V lim is the dynamic explosion threshold, β0, β1, and β2 are material characteristic coefficients, which are calibrated by coal powder explosion test experiments, PO2 is the oxygen enrichment pressure, and T g is the gas temperature; Safety margin control: Set the upper limit of mixed volatile matter to meet the following requirements: Where V max is the upper limit of mixed volatile matter, γ is the safety factor, ranging from 0.5 to 1.0; Control the volatile matter of the mixed coal powder to meet V mix ≤V max .

5. The method for increasing the blast furnace coal ratio according to claim 1, characterized in that: The swirl guide plate structure design in step (S5): The guide plate inclination angle can be adjusted from 30° to 50°, and the surface is covered with a tungsten carbide wear-resistant layer; The oxygen flow channel is distributed in the form of an Archimedean spiral, and the pitch changes with the pressure gradient; The guide plate substrate is provided with a microporous nitriding cooling channel.

6. The method for increasing the blast furnace coal ratio according to claim 1, characterized in that: The slag phase analysis method of step (S6) specifically includes: (a) Slag sample preparation: The slag at the slag-iron interface was rapidly cooled and solidified, and then cut and polished to a mirror surface; (b) Image analysis: Scan the field of view under a 200x microscope to identify the outline of the iron bead; (c) Calculation of unburned rate: Calculate the area ratio of iron balls with diameters greater than 50 μm and convert the unburned rate of pulverized coal into the following formula:

7. The method for increasing the blast furnace coal ratio according to claim 1, characterized in that: Method for constructing the cost-performance function in step (S4): Where λ1+λ2+λ3=1, and λ3≥0.4; Coal type screening rules: give priority to the coal types with the top three η values, and allocate the mixing ratio according to the difference in activation energy of the elementary reactions.

8. The method for increasing the blast furnace coal ratio according to claim 1, characterized in that: Step (S5) of the hierarchical oxygen supply strategy: Low-pressure oxygen (0.05-0.15 MPa) is injected into the cold air main through an annular distributor, with an oxygen concentration gradient of ≤5% / m; High-pressure oxygen (2.0-3.5 MPa) is accelerated to supersonic speed through the Laval nozzle and injected tangentially at a distance of 2.0±0.3 m from the tuyere.

9. The method for increasing the blast furnace coal ratio according to claim 1, characterized in that: Flow balancing control method of step (S2): (a) Deviation detection: Take 32 air outlets as monitoring units and calculate the flow standard deviation σ: (b) Adjustment strategy: When σ>8%, open the taper valve for graded adjustment: For over-flow tuyere, close it step by step (each step ≤ 2% opening) The underflow tuyere is opened in a pulsed manner using high-frequency short pulses.

10. The method according to claim 1, characterized in that Feedback adjustment logic of step (S6): (I) When CO / CO2<0.25, ΔO2=K1e -t / τ The function increases the oxygen enrichment, where K1 is the base increment and τ is the furnace capacity time constant; (II) When the unburned rate is greater than 5%, a two-level response is initiated: Primary response: coal injection rate decreases at a slope of -0.5t / (h·min) Secondary response: When the unburned rate is >8%, inject the combustion-supporting catalyst.

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