Oxygen enrichment type blast furnace operation method

Abstract

The present invention discloses an oxygen-enriched blast furnace operation method, in which after the furnace is warmed up, a charge is loaded, heated nitrogen gas is blown in through the tuyere to preheat, and then hot coal gas and oxygen gas are sent through the tuyere to control the theoretical combustion temperature to be 2350-2400°C. When the theoretical amount of iron in the furnace can reaches 60% of the normal safe allowable amount of iron, iron is tapped. Then, the input load is gradually increased, and the input amounts of reducing gas and oxygen gas are increased to achieve normal tapping and load adjustment in the furnace, and the theoretical combustion temperature at this stage is 2400-2500°C. In the present invention, heated nitrogen gas is blown onto the raw materials, thereby quickly and effectively drying the raw materials and raising the raw material temperature, and the blast furnace coal gas system can be made to run smoothly. In addition, heated reducing coal gas is blown into the furnace through the tuyere, so that the high-temperature, highly reducing coal gas can immediately participate in the reduction reaction with the charge at the top after entering the furnace. When combusted together with the blown-in oxygen gas, a large amount of heat is released, which quickly raises the temperature of the furnace can, shortens the blast furnace operation time, and effectively reduces the consumption of raw fuel.

Description

[Technical field]

[0001] The present invention relates to the technical field of blast furnace iron making, and in particular to a method for operating a blast furnace by injecting coal gas with oxygen enrichment. [Background technology]

[0002] In conventional blast furnace operation, sinter, pellets, coke, and solvent are mixed in a certain ratio to form a charge, and the charge is charged into the furnace from the top, and then hot air is blown into the blast furnace through the tuyere. When the charge moves in contact with the hot air in the blast furnace, heat transfer and oxidation-reduction reactions occur, generating coal gas. The coal gas moves upward and leaves the blast furnace through the riser. The blast furnace raw materials melt during the reaction process and drip as molten iron and slag, and the liquid slag is discharged from the blast furnace through the tap hole. In conventional blast furnace operation, in the early stages, the heat storage process of the furnace can is slow, the calorific value of the coal gas is low, the utilization rate of the coal gas fluctuates greatly, and the indirect reduction process is insufficient. In the operation process, blast furnace operators generally increase the amount of coke and operate with a super-light load charge to accelerate the rate of oxygen reduction reaction in the blast furnace. However, this method of operation results in high fuel consumption and a long reaction period, while the furnace cans must go through an extremely cold and hot process, making the furnace front work more difficult and risky. Summary of the Invention [Problem to be solved by the invention]

[0003] The present invention aims to provide a new method for operating a blast furnace with oxygen enrichment in order to ensure safer operation of the blast furnace, higher efficiency, reduced carbon emissions, and economical operation goals. [Means for solving the problem]

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] An oxygen-enriched blast furnace operation method, comprising: Furnace warming work (S1) 1) Fully open the mixed gas valve to send cold air. After the air is sent, the pressure at the top of the furnace is set to 10 kPa and the air volume is 300 m 3 2) After the air temperature and the air volume are stabilized, the gas mixing valve is manually adjusted to control the actual air temperature rise according to the temperature rise curve, and after the air temperature is stabilized at 150°C according to the temperature at the tip of the tuyere, the air volume is set to 400-500 m 3 / min, and when the air temperature exceeds 400°C, the air volume is increased to 500 m 3 / min, and when the temperature drops below 400°C during the temperature drop period, the air volume is set to 400 m 3 During the process of increasing the temperature or air volume, the temperature at the top of the furnace is kept below 250°C and the temperature of the airtight box is kept below 50°C. If the temperature at the top of the furnace exceeds 250°C, the air volume is increased to 50m 3 / min / times, and gradually decreasing the average air volume to 0 after 24 to 26 hours (S1); Charge preparation work (S2), in which after the furnace warm-up is finished, the charge preparation is started, first, one batch of pure coke is put into the bottom of the furnace, then a coil pipe for drawing out coal gas from the tap hole is installed, one batch of pure coke is put in, sleepers are put into the furnace can, and then a load charge is put into the middle and lower part of the furnace body, so that the coke rate is 1500-1800 kg / t, coke with a load charge is put into the middle part of the furnace body, so that the coke rate is 1100-1300 kg / t, coke with a load charge is put into the upper part of the furnace body, so that the coke rate is 800-1000 kg / t, and normal charge is put into the furnace throat and the upper part of the furnace body, so that the coke rate is 500-600 kg / t (S2); After the charge is finished, the nitrogen gas is cooled or heated and then blown, and the pressure and flow rate of the nitrogen gas is adjusted by a group of control valves, and the nitrogen gas enters a heating device, passes through a blower header pipe, a shroud pipe, and a branch pipe, and then enters the blast furnace from the tuyere. First, room temperature nitrogen gas is blown into the charge for 1 hour, and then the heating device is started to increase the temperature of the nitrogen gas at a rate of 300°C / h. After 2.5 hours, if the temperature of the nitrogen gas entering the furnace reaches 900 or more, the heated nitrogen gas is blown into the raw material for 2 hours to quickly and effectively increase the temperature of the raw material. During that period, the blast furnace is opened to allow ventilation, and nitrogen gas is blown into the coal gas pipeline network to blow into the furnace and the coal gas pipeline network, and the pipe for discharging the coal gas in the tap hole is opened to perform the dust removal function of the tap hole (S3). After blowing high-temperature nitrogen gas at 900 to 1200 ° C for 2 to 4 hours at a constant temperature, the reducing coal gas injection system in the tuyeres is started, and the reducing coal gas is CO: 60 to 75%, CO 2 :5%, H 2 : 10-15%, O 2 0.5%, and the valve group of the reducing coal gas injection system is controlled to a predetermined flow rate (10,000 to 15,000 m 3 / h), and turn on the reducing coal gas quick switching valve and the flow rate control valve, so that the reducing coal gas enters the heating device, mixes with the nitrogen gas and is heated, and then passes through the blower header pipe, the enclosure pipe, and the branch pipe, and then enters the blast furnace through the tuyere; and the heating target temperature is set to 900-1200°C, and the reducing coal gas is heated before being blown into the tuyere, so that the purpose of quickly increasing the temperature of the furnace can only be achieved by the high-temperature reducing coal gas; and after the high-temperature reducing coal gas enters the furnace, it can immediately participate in the reduction reaction with the upper load charge, and the oxygen iron in the raw material is reduced and then enters the furnace can in the form of metallic iron; and the tap hole is provided with 2-3 torches, so that the coal gas can be burned after it bubbles up from the tap hole; and taking measures for monitoring the coal gas in each area and preventing coal gas poisoning (S4); After introducing high-temperature reducing coal gas of 900 to 1200°C or higher into the furnace and injecting it for 1 to 2 hours, the oxygen gas injection system in the tuyere is started and oxygen gas is injected into the tuyere at a rate of 15,000 to 25,000 m 3 / h blowing step (S5), After the oxygen gas injection system is started, the pressure and flow rate of the oxygen gas are adjusted by the oxygen gas valve stand, and then the oxygen gas is mixed with the high-temperature reducing coal gas and high-temperature nitrogen gas in the passage of the small sleeve in the tuyere, and enters the blast furnace. An ignition operation (S6) is performed to ignite the high-temperature coal gas and the coke in front of the tuyere at the tip of the small sleeve; After the ignition at the tuyere is successful, the amount of nitrogen gas injected is decreased, and during that period, the oxygen content of the total amount injected at the tuyere is adjusted to be 75-100%, while the amount of coal gas injected is gradually increased, and the heating temperature of the coal gas is increased to 1100-1200°C, so that the theoretical combustion temperature before the tuyere is controlled to be within the range of 2350-2400°C (S7); The coal gas components at the furnace top are continuously monitored, and O 2After the content of NH3 is less than 1% and the content of CO exceeds 16%, the output coal gas is deemed to meet the conditions for recovery into the pipeline, and the grid-connected double-valve and the cutoff valve are turned on to make the furnace top unventilable, thereby completing the operation of introducing the coal gas into the pipeline; after the introduction of the coal gas is completed, the pressure at the top begins to increase to 60-100 Kpa, and as much of the initial high-temperature coal gas in the tuyere area is blown out of the tap hole as much as possible, thereby achieving the purpose of heating the furnace can and the raw materials in the furnace can (S8); A step (S9) of stabilizing the amount of oxygen gas entering the furnace and increasing the amount of hot coal gas blown from the tuyere to maintain the wind speed at the tuyere at 200 to 250 m / s and the theoretical combustion temperature at the tuyere at 2350 to 2400°C, and when it is calculated that the theoretical amount of iron in the furnace can has reached 60% of the normal safe allowable amount of iron, opening the tap hole to perform the first tapping; A step (S10) of gradually increasing the inlet load and increasing the inlet amount of the reducing coal gas to adjust the theoretical combustion temperature at the tuyere to 2400 to 2500 ° C.; Next, the method includes a step (S11) of performing normal tapping and adjusting the load in the furnace according to the calculated theoretical molten iron production volume and the safe allowable iron content of the blast furnace, completing the silicon reduction work of the molten iron, and achieving the operational goal of making the oxygen-enriched blast furnace safe. Effect of the Invention

[0006] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0007] In the method according to the present invention, the raw material is blown with heated nitrogen gas, so that the raw material can be dried and the raw material temperature can be raised quickly and effectively, and the heat of the furnace can in the subsequent stage is sufficient, and the reduction reaction by the highly reducible reducing coal gas can be carried out efficiently. In addition, hot nitrogen gas is blown through the tuyere to preheat the charge and dry the charge, while the system is inert, so that preparations are made for the supply of nitrogen gas and coal gas. The technical means of heating the reducing coal gas before blowing it through the tuyere can achieve the purpose of quickly raising the furnace can temperature, and after the high-temperature highly reducible coal gas enters the furnace, it can immediately participate in the reduction reaction with the charge at the top, so that the temperature of the slag generated after the load charge enters the furnace can is sufficient, and the entire process from smelting to the furnace can be carried out stably and efficiently. When the hot coal gas is blown in, the reducing gas immediately carries out an oxygen reduction reaction with the charge, generating heat. In this process, the flow of the coal gas generation process in the conventional blast furnace operation is skipped, and the hot coal gas is directly reacted with the charge, and oxygen gas is blown in from the tuyere to react with the coal gas, intensifying the process of oxygen reduction reaction, so that the consumption of raw fuel is reduced by 60% compared to the conventional blast furnace, and the overall fuel ratio in the blast furnace operation is 800 kg / t. In addition, since the blast furnace operation is performed by blowing the coal gas with all oxygen, the amount of coal gas in the furnace is smaller than that of the conventional blast furnace, and the blast furnace operation can be performed smoothly. In addition, the ignition operation is further simplified, so that the ignition operation can be completed by only sending oxygen gas, and compared to the COREX process, which is also a pure oxygen smelting, there is no need for an operator to perform ignition operation at the tuyere, which is superior. Finally, oxygen gas is directly injected into the furnace through the tuyere to maintain the theoretical combustion temperature before the tuyere in the range of 2350-2400°C, and the oxygen gas and reducing coal gas are mixed in the small sleeve passage in the tuyere and then injected into the furnace to enhance the intensity of smelting. [Brief description of the drawings]

[0008] [Figure 1] 1 is a graph of temperature rise according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The following clearly and completely describes the technical solutions of the embodiments of the present invention. It is obvious that the described embodiments are only some of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments that can be obtained by those skilled in the art without any creative efforts are all within the protection scope of the present invention.

[0010] The present invention provides the following technical solutions:

[0011] The oxygen enrichment type blast furnace operating method includes the following steps. In the furnace warming work (S1), 1) Fully open the mixed gas valve to send in cold air. After the air is sent, set the pressure at the top of the furnace to 10 kPa and the air volume to 300 m 3 Set it to / min, 2) After the air temperature and volume are stabilized, manually adjust the gas mixing valve to control the actual air temperature rise according to the temperature rise curve, according to the temperature at the tip of the tuyere. The temperature rise curve is as shown in Figure 1. After the air temperature is stabilized at 150℃, the air volume is set to 400~500m 3 / min, and when the air temperature exceeds 400°C, the air volume is increased to 500m 3 / min, if the temperature drops below 400°C during the temperature drop period, the air volume will be increased to 400 m 3 During the process of increasing the temperature or air volume, the temperature at the top of the furnace should be kept below 250°C and the temperature of the airtight box should be kept below 50°C. If the temperature at the top of the furnace exceeds 250°C, the air volume should be increased to 50m 3 / min / times, and gradually decreasing so that the average airflow reaches 0 after 24 to 26 hours.

[0012] In the charge loading work (S2), after the furnace warm-up is completed, the loading of the charge is started. First, one batch of pure coke is loaded into the bottom of the furnace, then a coil pipe for drawing out coal gas is installed from the tap hole, one batch of pure coke is loaded, sleepers are placed in the furnace can, and then a load charge is loaded into the middle and lower part of the furnace body to set the coke rate to 1500 to 1800 kg / t, coke with a load charge is loaded into the middle part of the furnace body to set the coke rate to 1100 to 1300 kg / t, coke with a load charge is loaded into the upper part of the furnace body to set the coke rate to 800 to 1000 kg / t, and normal charge is loaded into the furnace throat and the upper part of the furnace body to set the coke rate to 500 to 600 kg / t.

[0013] In step (S3), after the charge is charged, nitrogen gas is cooled and heated before being blown. The pressure and flow rate of the nitrogen gas are adjusted by the control valve group, and then the nitrogen gas enters the heating device, passes through the blast header pipe, the enclosure pipe, and the branch pipe, and then enters the blast furnace through the tuyere. First, room temperature nitrogen gas is blown in to blow the charge for 1 hour, then the heating device is started to increase the temperature of the nitrogen gas at a rate of 300°C / h. After 2.5 hours, if the temperature of the nitrogen gas entering the furnace reaches 900 or higher, the heated nitrogen gas is blown into the material for 2 hours to quickly and effectively increase the temperature of the material. During that period, the blast furnace is opened to allow ventilation, and nitrogen gas is blown into the coal gas pipeline network to blow into the furnace and the coal gas pipeline network. The pipe for discharging the coal gas at the tap hole is opened to achieve the dust removal function of the tap hole.

[0014] In step (S4), after blowing high-temperature nitrogen gas at 900 to 1200°C at a constant temperature for 2 to 4 hours, the reducing coal gas injection system at the tuyere is started, and the valve group of the reducing coal gas injection system is opened and closed at a predetermined flow rate (10,000 to 15,000 m 3The furnace starts at 1000 rpm (1200 rpm), and the reducing coal gas quick switching valve and the flow rate control valve are turned on, so that the reducing coal gas enters the heating device, is mixed with nitrogen gas and heated, passes through the blower header pipe, the enclosure pipe and the branch pipe, and then enters the blast furnace through the tuyere. The target heating temperature is set at 900-1200°C, and the reducing coal gas is heated before being blown into the tuyere. The high-temperature reducing coal gas alone can achieve the purpose of quickly increasing the temperature of the furnace can. After the high-temperature reducing coal gas enters the furnace, it can immediately participate in the reduction reaction with the upper load charge, and the oxygen iron in the raw material can enter the furnace can in the form of metallic iron after being reduced. Two or three torches are installed at the taphole to ensure that the coal gas can be burned after it emerges from the taphole. Regional coal gas monitoring measures and measures to prevent coal gas poisoning are taken.

[0015] In step (S5), high-temperature reducing coal gas of 900 to 1200°C or higher is introduced into the furnace and injected for 1 to 2 hours, and then the oxygen gas injection system at the tuyere is started, and oxygen gas is injected into the tuyere at a rate of 15,000 to 25,000 m 3 Blow in at / h.

[0016] In the ignition operation (S6), after the oxygen gas injection system is started, the pressure and flow rate of the oxygen gas are adjusted by the oxygen gas valve stand, and then the oxygen gas is mixed with the high-temperature reducing coal gas and high-temperature nitrogen gas in the passage of the small sleeve in the tuyere and enters the blast furnace, where it ignites the high-temperature coal gas and the coke in front of the tuyere at the tip of the small sleeve.

[0017] In step (S7), after successful ignition at the tuyere, the amount of nitrogen gas injected begins to decrease, and during that period, the oxygen content of the overall amount injected at the tuyere is adjusted to be 75-100%, while the amount of coal gas injected is gradually increased, and the heating temperature of the coal gas is increased to 1100-1200°C, so that the theoretical combustion temperature before the tuyere is controlled to be in the range of 2350-2400°C.

[0018] In step (S8), the coal gas components at the furnace top are continuously monitored and O2 When the content of H2O is less than 1% and the content of CO exceeds 16%, the output coal gas is deemed to meet the conditions for recovery into the pipeline, and the grid-connected double-valve and cut-off valve are turned on to make the furnace top unventilable, thereby completing the introduction of the coal gas into the pipeline. After the introduction of the coal gas is completed, the pressure at the top begins to increase to 60~100Kpa, and as much of the initial high-temperature coal gas in the tuyere area as possible is blown out from the tap hole to achieve the purpose of heating the furnace can and the materials in the furnace can.

[0019] In step (S9), the amount of oxygen gas entering the furnace is stabilized, and the amount of high-temperature coal gas injected from the tuyere is increased to maintain the wind speed at the tuyere at 200 to 250 m / s and the theoretical combustion temperature at the tuyere at 2350 to 2400°C. When it is calculated that the theoretical amount of iron in the furnace can has reached 60% of the normal safe allowable iron amount, the tap hole is opened and the first tapping is performed.

[0020] In step (S10), the input load is gradually increased, and the amount of reducing coal gas input to the furnace is increased to adjust the theoretical combustion temperature at the tuyere to 2400 to 2500°C.

[0021] In step (S11), normal tapping and load adjustment in the furnace are performed according to the calculated theoretical molten iron production volume and the safe allowable iron content of the blast furnace, and the silicon reduction work of the molten iron is completed to achieve the operational goal of making the oxygen-enriched blast furnace safe.

Claims

1. After the furnace was warmed up, the charge was loaded and heated nitrogen gas was blown into the tuyeres for 5 hours to preheat the charge and to coast the blast furnace coal gas system. Then, hot coal gas and oxygen gas are fed through the tuyere and controlled so that the theoretical combustion temperature is 2350-2400°C; When the theoretical iron content in the furnace reaches 60% of the normal safe allowable iron content, the iron is tapped. Subsequently, gradually increase the load on the furnace and increase the amount of reducing gas entering the furnace, and control the theoretical combustion temperature at this stage to 2400-2500°C, so as to achieve normal tapping and load adjustment in the furnace. The oxygen-enriched blast furnace operation method according to the present invention is characterized in that

2. The furnace is heated for 24 hours by introducing heated and compressed air into the hot air stove (S1). After the furnace warm-up is completed, the charge is started, and first, one batch of pure coke is put into the bottom of the furnace, then a coil pipe for drawing out coal gas from the tap hole is installed, pure coke is put in, sleepers are put into the furnace can, and then a load charge is put into the middle and lower part of the furnace body, and the coke rate is 1500 to 1800 kg / t, coke with a load charge is put into the middle part of the furnace body, and the coke rate is 1100 to 1300 kg / t, coke with a load charge is put into the upper part of the furnace body, and the coke rate is 800 to 1000 kg / t, normal charge is put into the furnace throat and the upper part of the furnace body, and the coke rate is 500 to 600 kg / t, and the overall coke rate of the operating charge is 800 to 900 kg / t (S2); After the charge preparation work is completed, nitrogen gas is cooled and heated and then blown. The pressure and flow rate of the nitrogen gas are adjusted by a control valve group, and then the nitrogen gas enters the heating device, passes through a blower header pipe, an enclosure pipe, and a branch pipe, and then enters the blast furnace from the tuyere. First, room temperature nitrogen gas is blown in to blow the charge for 1 hour, and then the heating device is started to increase the temperature of the nitrogen gas at a rate of 300°C / h. After 2.5 hours, the temperature of the nitrogen gas entering the furnace reaches 900 to 1200°C or more. In this case, the heated nitrogen gas is blown against the raw material for 2 to 4 hours to quickly and effectively raise the temperature of the raw material. During that period, the blast furnace is opened to allow ventilation, and nitrogen gas is blown through the coal gas pipeline network to blow it into the furnace and the coal gas pipeline network. The pipe for drawing out the coal gas in the tap hole is opened, and the dust removal function for the tap hole is exerted (S3); After blowing high-temperature nitrogen gas at 900 to 1200°C for 2 to 4 hours at a constant temperature, the reducing coal gas injection system at the tuyere is started, and the valve group of the reducing coal gas injection system is opened and closed at a predetermined flow rate of 10,000 to 20,000 m ３ / h, and turning on the reducing coal gas quick switching valve and the flow rate control valve, the reducing coal gas enters the heating device, mixes with nitrogen gas and is heated, passes through the blower header pipe, the enclosure pipe, the branch pipe, and enters the blast furnace from the tuyere; and the heating target temperature is set to 900-1200°C, the reducing coal gas is heated and then blown into the tuyere, so that the purpose of quickly increasing the temperature of the furnace can only be achieved by the high-temperature reducing coal gas; and after the high-temperature reducing coal gas enters the furnace, it can immediately participate in the reduction reaction with the upper load charge, and it is ensured that the oxygen iron in the raw material is reduced and then enters the furnace can in the form of metallic iron; and the tap hole is provided with 2-3 torches, so that it is ensured that the coal gas can be burned after it bubbles up from the tap hole; and taking measures for monitoring the coal gas in each area and preventing coal gas poisoning (S4); After introducing high-temperature reducing coal gas of 900°C or higher into the furnace and injecting it for 1 to 2 hours, the oxygen gas injection system in the tuyere is started and oxygen gas is injected into the tuyere at a rate of 15,000 to 25,000 m ３ / h blowing step (S5); After the oxygen gas injection system is started, the pressure and flow rate of the oxygen gas are adjusted by the oxygen gas valve stand, and then the oxygen gas is mixed with the high-temperature reducing coal gas and high-temperature nitrogen gas in the passage of the small sleeve in the tuyere, and enters the blast furnace. An ignition operation (S6) is performed to ignite the high-temperature coal gas and the coke in front of the tuyere at the tip of the small sleeve; After the ignition at the tuyere is successful, the amount of nitrogen gas injected is decreased, and during this period, the oxygen content of the total amount of injected gas at the tuyere is adjusted to be 75-100%, while the amount of coal gas injected is gradually increased, and the heating temperature of the coal gas is increased to 1100-1200°C, so that the theoretical combustion temperature before the tuyere is controlled to be in the range of 2350-2400°C (S7); Continuously monitor the coal gas components at the furnace top and ２ After the content of Zn is less than 1% and the content of CO exceeds 16%, the output coal gas is deemed to meet the conditions for recovery into the pipeline, and the grid-connected double-valve and the cutoff valve are turned on to make the furnace top unventilable, thereby completing the operation of introducing the coal gas into the pipeline; after the introduction of the coal gas is completed, the pressure at the top begins to increase to 60-100 Kpa, and the initial high-temperature coal gas in the tuyere region is blown out from the tap hole, thereby achieving the purpose of heating the furnace can and the raw materials in the furnace can (S8); A step (S9) of adjusting the amount of oxygen gas entering the furnace and synchronously adjusting the amount of hot coal gas blown from the tuyere to maintain the wind speed at the tuyere at 200 to 250 m / s and the theoretical combustion temperature at the tuyere at 2350 to 2400°C, and when it is calculated that the theoretical amount of iron in the furnace can has reached 60% of the normal safe allowable amount of iron, opening the tap hole to perform the first tapping; Step (S10) of gradually increasing the input load and increasing the input amount of reduced coal gas to adjust the theoretical combustion temperature at the tuyere to 2400 to 2500 ° C.; Then, in accordance with the calculated theoretical hot metal production amount and the safe allowable iron amount of the blast furnace, normal tapping and load adjustment in the furnace are performed, and silicon reduction of the hot metal is completed, thereby achieving the operation goal of making the oxygen-enriched blast furnace safe (S11).

2. The method for operating an oxygen-enriched blast furnace according to claim 1 .

3. Before the blast furnace operation, first blow cold nitrogen gas into the raw materials and the coal gas system, then start the heater to heat the nitrogen gas and blow the charge to preheat it; Then, CO: 60-75%, CO ２ : 5%, H ２ : 10-15%, O ２ : The charge is preheated and reduced using reducing coal gas having a composition of 0.5%, and finally, oxygen gas is blown in to ignite the charge, thereby performing blast furnace operation.

2. The method for operating an oxygen-enriched blast furnace according to claim 1 .

4. The raw materials in the furnace are blown with hot nitrogen gas, then with hot coal gas to reduce them, and oxygen gas is blown directly from the tuyere to ignite the coke and reducing coal gas in the furnace, thereby realizing ignition for blast furnace operation; By adjusting the injection amount of the reducing coal gas and the nitrogen gas in the furnace, the theoretical combustion temperature at the tuyere is set to 2350-2400°C, and then, within a reasonable range, while introducing oxygen gas, the injection amount of the reducing coal gas is gradually increased and the amount of nitrogen gas introduced into the furnace is decreased, thereby gradually realizing an injection type smelting mode by all oxygen gas and reducing coal gas at the tuyere; After the blast furnace is operating normally, the oxygen gas injection rate per ton of molten iron is set at 200 to 300 m ３ / t, and the amount of reducing coal gas injected per ton of molten iron is 500 to 750 m ３ / t, and the temperature of the reducing coal gas is 900 to 1200 ° C.; 2. The method for operating an oxygen-enriched blast furnace according to claim 1 .

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