Reblowing operation method of hydrogen-rich carbon circulating oxygen blast furnace

Abstract

The invention belongs to the technical field of blast furnace smelting, and particularly discloses a reblowing operation method of a hydrogen-rich carbon circulating oxygen blast furnace. The method is executed based on a reblowing program confirmation table and sequentially comprises three stages of connection and confirmation before air supply, air supply, coal gas grid connection and coal gas injection. The operation sequence, responsible persons and key parameters of all stages are defined through a systematic operation process, orderly use and cooperative control of nitrogen, oxygen and decarburized coal gas are achieved, out-of-control of the oxygen concentration and abnormal theoretical combustion temperature are effectively avoided, and therefore safe and controllable and stable transition of the whole reblowing process is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of blast furnace smelting, in particular to a method for blast recovery operation of a hydrogen-rich carbon-circulation oxygen blast furnace. BACKGROUND

[0002] In the blast recovery process of a traditional blast furnace after maintenance, there are often problems such as unstable air supply, high safety risk of the gas system, uneven mixing of oxygen and gas, and difficult control of the furnace top pressure. In a hydrogen-rich carbon-circulation oxygen blast furnace, the blast recovery process is more complex due to the coordinated control of nitrogen, oxygen, and decarburization gas. The existing technology lacks systematic operation guidelines for such a blast furnace, resulting in safety hazards such as tuyere blockage, gas leakage, and uncontrolled oxygen concentration during the blast recovery process. In particular, in key links such as decarburization gas commissioning and oxygen-gas ratio control, there is a lack of clear operation sequence, parameter control standards, and responsibility division, making it difficult to achieve safe and controllable and smooth transition during the blast recovery process. SUMMARY

[0003] The present application relates to the technical field of blast furnace smelting, in particular to a method for blast recovery operation of a hydrogen-rich carbon-circulation oxygen blast furnace.

[0004] To achieve the above-mentioned purpose, the basic scheme provided by the present application is: a method for blast recovery operation of a hydrogen-rich carbon-circulation oxygen blast furnace, the method is based on a blast recovery program confirmation table, which specifies operation classification, operation sequence, operator, matters needing attention, modification record, key parameters and time nodes; the method comprises the following three stages in turn: The first stage is pre-blast communication and confirmation, including closing the backflow valve, checking the nitrogen purge of the gas system, preparing the raw fuel and water system, confirming that the decarburization gas pipeline pressure relief valve is closed, opening the oxygen injection platform security nitrogen hand valve total valve and sending nitrogen pressure, opening the oxygen injection platform 2-way oxygen branch hand valve total valve, opening the nitrogen hand valve total valve of the coal gas injection valve table, and notifying the shift supervisor and raw material preparation to send blast; The second stage is blast, including initial blast and nitrogen establishment, blast gun injection blast, confirming that the blast valve table coal gas security nitrogen is sent to the blast valve after the blast valve is opened, notifying the blast operation of the coal gas heating furnace, closing the blast valve, sending hot nitrogen gas to the specified flow rate of the coal gas heating furnace, sending oxygen operation and checking after sending oxygen; The third stage is coal gas network and injection of coal gas, including opening the gravity shut-off valve, opening the bag house outlet butterfly valve for coal gas network, closing the furnace top diffuser, adding nitrogen and oxygen, adjusting the furnace top pressure, opening the coal gas shut-off valve and regulating valve in the decarburization area, sending decarburization gas, and gradually increasing the load until the target operating state is reached.

[0005] Further, the oxygen feeding operation includes: opening oxygen hand valves of multiple tuyeres, closing additional nitrogen, adjusting security nitrogen flow to 15000 m 3 / h, waiting for 2-5 minutes before feeding large pipe oxygen, and stopping security nitrogen after oxygen pipe flow is stable.

[0006] Further, the flow of the large pipe oxygen feeding is 20000 m 3 / h.

[0007] Further, in the process of gradually increasing the load, the decarburized gas is increased by 10000 m 3 / h each time, and the oxygen is increased by 3000 m 3 / h.

[0008] Further, in the process of gradually increasing the load, the theoretical combustion temperature is controlled at 2000-2200℃.

[0009] Further, the decarburized gas feeding includes: confirming that the purging nitrogen of the cold and hot gas pipe blind ends is in an open state and is qualified for purging; opening the electric valve at the end of the coal gas injection valve table; after confirming that the nitrogen flow is greater than 35000 m 3 / h, opening the coal gas quick switching valve, and then opening the coal gas flow regulating valve by 1% each time until the initial flow reaches 30000 m 3 / h.

[0010] Further, the initial air feeding and nitrogen establishment includes: opening the additional nitrogen branch valves of multiple tuyere oxygen channels to 10% opening, and opening the spherical branch valves of each tuyere blowing pipe; feeding security nitrogen to the front end of the specified valve, opening its cut-off valve, and opening the flow regulating valve to 15%.

[0011] Further, the notification of the coal gas heater feeding operation includes: the coal gas heating worker ensures that multiple hot blast furnaces are purged with nitrogen for 2-5 minutes before feeding, ensures that the oxygen content of the flue is <1%, and specifies a hot blast furnace as a coal gas feeding hot blast furnace.

[0012] Further, the nitrogen and oxygen amount includes: gradually adding nitrogen to 50000 m 3 / h, and synchronously adding oxygen to 15000 m 3 / h; then, adjusting the furnace top pressure according to the comprehensive air volume and hot gas pressure; synchronously opening the tuyere oxygen channel valve, and the control standard is to open one tuyere for every 1000 m 3 / h of oxygen amount.

[0013] Further, after reaching the target air volume, the state is maintained for more than 4 hours; the subsequent operation strategy is: reducing 10000 m 3 / h of hot nitrogen each time, and increasing 10000 m 3 / h decarburized coal gas.

[0014] Compared with the prior art, the application has the advantages that: Through systematic operation process based on the reblowing program confirmation table, the operation sequence, the person in charge and the key parameters of each stage are clear, the standardization management of the reblowing process is realized; through the pre-preparation, the blowing operation and the coal gas grid connection control in stages, the orderly use and collaborative control of nitrogen, oxygen, decarburized coal gas and other gases are ensured; through setting the security nitrogen transition and stable waiting time in the oxygen blowing operation and controlling the ratio of decarburized coal gas and oxygen in the process of load increase, the oxygen concentration out of control and the abnormal theoretical combustion temperature are effectively avoided, so that the safe controllability and smooth transition of the whole process of the hydrogen-rich carbon cycle oxygen blast furnace reblowing are realized. DETAILED DESCRIPTION

[0015] The application will be further described in detail through specific embodiments: A reblowing operation method of a hydrogen-rich carbon cycle oxygen blast furnace, which is executed based on a detailed reblowing program confirmation table. The confirmation table specifies the operation classification, operation sequence, operator, matters needing attention, modification record, key parameters and time node in the form of a table. The operation classification includes valve operation, gas flow control, system check and the like; the operation sequence is arranged according to time; the operator is clear for specific posts such as shift foreman, coal gas heating worker, coal injection worker and the like; the matters needing attention lists safety requirements and inspection points; the key parameters include the numerical range of each gas flow, pressure, temperature and the like; the time node records the actual execution time of each step. It can be understood that the confirmation table serves as an operation guide file to ensure that each post personnel executes the operation according to the unified standard. The method of the application includes the following three stages: In the first stage of pre-blowing communication and confirmation, the following steps are specifically included: first, the shift foreman operates to close the backflow valve, confirms that the maintenance work is completed, and confirms that the furnace top diffuser valve is in the open state. Then check the nitrogen blowing of the coal gas system, confirm that the nitrogen is introduced into the furnace top and gravity dust collector, and confirm that the 10 bag-type dust collector outlet butterfly valves are in the closed state. Then, the original fuel preparation communication and the water system and slag flushing system communication are carried out. Then, confirm that the DN800 pressure relief valve of the coal injection pipeline is closed, and at the same time, confirm that the decarburization region inlet cut-off valve and regulating valve are closed. In terms of gas pipeline preparation, first confirm that the DN80 hand valve and DN50 hand valve of the tuyere platform oxygen ring are closed, then open the oxygen injection platform security nitrogen hand valve total valve, and send nitrogen to the pipeline for pressure preservation. At the same time, open the oxygen injection platform 2-way oxygen branch pipe hand valve total valve, and confirm that the oxygen flow regulating valve and cut-off valve are in manual mode and in the closed position before operation. Similarly, before opening the coal gas injection valve platform nitrogen hand valve total valve, confirm that the nitrogen flow regulating valve and cut-off valve are in manual mode and in the closed position. Finally, inform the shift supervisor and the raw material post to prepare for blowing.

[0016] In the second stage of the blowing operation, the initial blowing and nitrogen are established by the shift foreman, which specifically includes: opening the additional nitrogen branch valve of the 30 tuyere oxygen channel, with the opening degree controlled at 5-15%, preferably 10%; and opening the tuyere blowpipe spherical branch valve. The security nitrogen is sent to the front end of the DN50 valve, the shut-off valve is opened, and the flow regulating valve is opened to 10-20%, preferably 15%. The coal injection gun blowing wind is operated by the coal injection worker, the coal injection post is notified to send the injection blowing wind, and the coal gun valve is opened. At this time, the parameters such as the comprehensive air volume, hot N2, cold N2, O2, decarburization gas, furnace top pressure and oxygen concentration are monitored, and the oxygen concentration target range is controlled at 0.21-0.24.

[0017] After confirming that the air release valve is opened, the blowing valve table coal gas security nitrogen is blown by the shift foreman to the air release valve, and the given nitrogen flow is 8000-12000 m 3 / h, preferably 10000 m 3 / h, with the pressure controlled below 5kPa. The gas heating furnace blowing operation is completed by the shift foreman and the gas heating worker. The gas heating worker ensures that the three hot blast furnaces are purged with nitrogen for 2-5 minutes before blowing, ensures that the flue oxygen content is <1%, and designates the 3# hot blast furnace as the coal gas hot blast furnace. The air release valve is closed by the gas heating worker, and after blowing, the tuyere is checked for air leakage, and if there is air leakage, the operation is performed after the air leakage is handled.

[0018] The specific implementation of the oxygen sending operation is as follows: first, the shift foreman increases the nitrogen sent by the gas heating furnace to 35000-45000 m 3 / h, preferably 40000 m 3 / h. After the nitrogen is stable, the oxygen sending operation is performed according to the modified program: opening the oxygen DN50 hand valve of the 30 tuyeres, closing the additional nitrogen, adjusting the security nitrogen flow to 12000-18000 m 3 / h, preferably 15000 m 3 / h. After waiting for 2-5 minutes, the large pipe oxygen is sent, with the flow controlled at 15000-25000 m 3 / h, preferably 20000 m 3 / h. After the oxygen pipeline flow is stable, the security nitrogen is stopped. The comprehensive air volume is calculated as (hot N2 + cold N2 + O2) / 60, for example, hot N2 50000 m 3 / h, cold N2 6000 m 3 / h, O2 25000 m 3 / h, the comprehensive air volume is (50000+6000+25000) / 60=1350 m 3 / min. After 2 minutes of oxygen feeding, the waterworks informed the blast furnace that oxygen had been fed, and the person on the tuyere platform checked the tuyere and reported to the central control room. At this stage, the oxygen channel pressure must be greater than 0.15 MPa.

[0019] In the operation process of the third stage of gas grid connection and coal gas injection, first, the gravity block valve is opened by the coal gas heating worker, and after the furnace top bleeder valve is closed, the nitrogen gas is stopped from being fed to the furnace top, gravity dust collector and bag dust collector. Then, the four bag box outlet butterfly valves are opened for gas grid connection, and the furnace top bleeder is closed by the batcher. Then, the shift foreman performs the nitrogen and oxygen gas amount operation: gradually adds nitrogen gas to 45,000-55,000 m 3 / h, preferably 50,000 m 3 / h, and synchronously adds oxygen gas to 12,000-18,000 m 3 / h, preferably 15,000 m 3 / h. Subsequently, the furnace top pressure is adjusted according to the comprehensive air volume and hot gas pressure. The tuyere oxygen channel valve is synchronously opened, and the control standard is that one tuyere is used for every 800-1,200 m 3 / h of oxygen, preferably one tuyere is used for every 1,000 m 3 / h of oxygen.

[0020] In the decarburization gas feeding operation, it specifically includes: first, confirm that the nitrogen gas for purging the blind end of the cold and hot gas pipelines is in an open state and the purging is qualified; then, open the electric valve at the end of the injection gas valve table; confirm that the nitrogen gas flow is greater than 30,000-40,000 m 3 / h, preferably 35,000 m 3 / h, open the coal gas quick switching valve, and then open the coal gas flow regulating valve, each time by 0.5-2%, preferably 1%, until the initial flow reaches 25,000-35,000 m 3 / h, preferably 30,000 m 3 / h.

[0021] In the process of gradually increasing the load, a step-by-step adjustment strategy is adopted, which is as follows: Step one: set hot N2 25,000-30,000 m 3 / h, cold N2 3,000-5,000 m 3 / h, O2 35,000-45,000 m 3 / h, decarburization gas 100,000-120,000 m 3 / h, furnace top pressure 50-70 kPa, and the preferred parameters are hot N2 27,000 m 3 / h, cold N2 4,000 m 3 / h, O2 40,000 m 3 / h, decarburization gas 110,000 m 3 / h, furnace top pressure 60 kPa.

[0022] Step two: increase decarburization gas 8000-12000 m 3 / h, preferably 10000 m 3 / h, increase oxygen 2500-3500 m 3 / h, preferably 3000 m 3 / h, control theoretical combustion temperature at 1950-2250℃, preferably 2000-2200℃. Target is to increase decarburization gas to 55000-65000 m 3 / h, total oxygen to 30000-36000 m 3 / h, total gas plus nitrogen to 100000-120000 m 3 / h.

[0023] Step three: increase gas 12000-18000 m 3 / h, preferably 15000 m 3 / h, increase oxygen according to ratio, gradually pressurize to specified hot blast pressure, and simultaneously set four valve group to track target pressure.

[0024] Subsequent steps continue to adjust according to the wind increase table until the target state is reached: total wind volume 4000-4100 m 3 / min, hot N2 45000-55000 m 3 / h, cold N2 4500-5500 m 3 / h, O2 55000-60000 m 3 / h, decarburization gas 125000-135000 m 3 / h, furnace top pressure 145-155 kPa. After reaching the target wind volume, maintain this state for more than 4 hours. Subsequent operation strategy: decrease hot nitrogen 8000-12000 m 3 / h each time, while increasing decarburization gas 8000-12000 m 3 / h each time, to gradually optimize operating conditions.

[0025] Table 1 is a wind increase table integrated air flow hot N2 cold N2 O2 decarbonized gas furnace top pressure oxygen concentration 2720 35000 4000 14200 110000 100 0.087 2817 35000 4000 40000 90000 105 0.237 2983 35000 4000 40000 100000 120 0.223 3858 6500 5000 54000 166000 155 0.233 3900 30000 4000 50000 150000 180 0.214 3930 10000 3800 57000 165000 185 0.242 4050 9000 3500 60000 185000 185 0.252 The above-mentioned are only embodiments of the present application, and the common knowledge of specific structures and characteristics in the scheme is not described too much. It should be pointed out that for those skilled in the art, without departing from the structure of the present application, a number of modifications and improvements can be made, which should also be considered as the protection scope of the present application, which will not affect the effect and practicality of the patent. The protection scope claimed in this application should be subject to the content of its claims, and the specific implementation mode and the like recorded in the specification can be used to explain the content of the claims.

Claims

1. A method for re-blasting a hydrogen-rich carbon-recirculating oxygen blast furnace, characterized in that, The method is based on a re-air ventilation procedure confirmation form, which specifies the operation category, operation sequence, operator, precautions, modification records, key parameters, and time nodes; the method includes the following three stages in sequence: The first phase involves pre-air supply communication and confirmation, including closing the backflow valve, checking the nitrogen supply to the gas system, preparing raw materials and water systems, confirming that the pressure relief valve of the gas injection pipeline is closed, opening the main nitrogen hand valve of the oxygen injection platform and supplying nitrogen for pressure maintenance, opening the main hand valve of the two oxygen branch pipes of the oxygen injection platform, opening the main nitrogen hand valve of the gas injection valve platform, and notifying the duty supervisor and raw material suppliers to prepare for air supply. The second stage is air supply, including initial air supply and nitrogen establishment, coal gun injection, opening the injection valve after confirming the vent valve is open, coal gas safety nitrogen supply to the vent valve, notifying the coal gas heater to operate the air supply, closing the vent valve, supplying hot nitrogen to the coal gas heater to the specified flow rate, oxygen supply operation and post-oxygen supply inspection. The third stage involves connecting the gas grid and adding pulverized gas, including opening the gravity shut-off valve, opening the baghouse outlet butterfly valve to connect the gas grid, closing the furnace top vent, adding nitrogen and oxygen, adjusting the furnace top pressure, opening the gas shut-off valve and regulating valve to the decarbonization zone, supplying decarbonization gas, and gradually increasing the load until the target operating state is reached.

2. The method for re-blasting a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 1, characterized in that, The oxygen delivery operation includes: opening the oxygen manual valves of multiple air vents, closing the extra nitrogen supply, and adjusting the safety nitrogen flow rate to 15000 m³ / h. 3 / h, wait 2-5 minutes before sending oxygen into the main pipe, and stop the safety nitrogen after the oxygen pipeline flow stabilizes.

3. The method for re-blasting a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 2, characterized in that, The flow rate of oxygen supplied to the main tube is 20,000 m³ / h. 3 / h.

4. The method for re-blasting a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 1, characterized in that, During the gradual increase in load, the amount of decarbonized gas increased by 10,000 m³ each time. 3 / h, while increasing oxygen by 3000m 3 / h.

5. The method for re-blasting a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 4, characterized in that, During the gradual increase of load, the theoretical combustion temperature is controlled between 2000-2200℃.

6. The method for re-blasting a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 1, characterized in that, The process of supplying decarbonized gas includes: confirming that the purging nitrogen at the blind end of the cold and hot gas pipelines is in the open state and that the purging is qualified; opening the electric valve at the end of the injection gas valve platform; and confirming that the nitrogen flow rate is greater than 35,000 m³ / h. 3 After / h, open the gas quick-cut valve, then open the gas flow regulating valve, opening it by 1% each time, until the initial flow reaches 30000m³. 3 / h.

7. The method for re-blasting a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 1, characterized in that, The initial air supply and nitrogen establishment include: opening the additional nitrogen branch valves of multiple air outlet oxygen channels to 10% opening, and simultaneously opening the ball branch valves of each air outlet blowpipe; supplying safety nitrogen to the front end of the designated valve, opening its shut-off valve, and opening the flow regulating valve to 15%.

8. The method for re-blast operation of a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 1, characterized in that, The notification of the gas heating furnace air supply operation includes: the gas heating operator ensuring that multiple hot air furnaces are purged with nitrogen for 2-5 minutes before air supply, ensuring that the oxygen content in the flue is <1%, and designating one hot air furnace as the gas supply hot air furnace.

9. The method for re-blasting a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 1, characterized in that, The amount of nitrogen and oxygen added includes: gradually adding nitrogen to 50,000 m³. 3 / h, simultaneously increase oxygen to 15000m 3 / h; subsequently, adjust the furnace top pressure according to the overall air volume and hot gas pressure; simultaneously open additional oxygen duct valves at the tuyere, with a control standard of every 1000m 3 / h oxygen supply is used at one air outlet.

10. The method for re-blasting a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 1, characterized in that, After reaching the target airflow, maintain this operating state for more than 4 hours; the subsequent operation strategy is: reduce the airflow by 10,000 m³ each time. 3 / h hot nitrogen, while increasing by 10000m 3 / h decarbonized coal gas.