Diagnosis, treatment and recovery method for hydrogen-rich carbon circulating oxygen blast furnace suspension material

Abstract

The invention belongs to the technical field of blast furnace ironmaking, and particularly discloses a hydrogen-rich carbon circulating oxygen blast furnace suspended material diagnosis, treatment and recovery method which comprises the steps of suspended material confirmation and initial response, system decrement and safety prevention, parameter grading fine adjustment, extreme condition emergency disposal and system recovery and production restart which are executed in sequence. Standardized treatment of the suspended material is realized by orderly and synergistically adjusting the oxygen flow, the decarburized gas flow, the blast furnace top pressure and the security nitrogen. According to the method, the operation experience dependence is reduced, the treatment safety and efficiency are improved, and rapid and stable production recovery of the blast furnace is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of blast furnace ironmaking technology, and in particular to a method for diagnosing, treating and restoring suspended materials in a hydrogen-rich carbon-circulating oxygen blast furnace. Background Technology

[0002] Blast furnace ironmaking is a core process in the modern steel industry, and its stable and smooth operation is crucial. Suspended charge is a serious process failure in blast furnace smelting, manifested as a halt in the descent of the charge column, obstructed gas flow, abnormally high blast pressure, and increased pressure differential. Traditional methods for handling suspended charge rely primarily on the operator's experience and judgment, typically employing a "holding charge" operation combined with adjustments to blast volume and pressure. However, for modern large blast furnaces (typically 2500 m³ / h) employing new technologies such as hydrogen-rich carbon-circulating oxygen blasting, this is a different story. 3 Traditional methods for handling suspended materials (and above) have significant shortcomings: First, due to the involvement of multiple gaseous media such as oxygen, decarbonized gas, natural gas, pulverized coal, and safety nitrogen in the injection and circulation, the flow rates and pressures of each medium are coupled and have complex relationships, making it difficult for traditional single-mode airflow regulation to effectively address the issue. Second, the system has strict safety interlocks, and traditional methods do not systematically consider how to correctly and orderly release and restore these interlocks during accident handling. Third, due to the high oxygen concentration, violent reaction, and rapid changes in the furnace's thermal state, the adjustment precision and timing of parameters such as oxygen and decarbonized gas are extremely important when handling suspended materials; careless operation can easily lead to the escalation of accidents. Finally, existing technologies lack a complete and standardized operating procedure for this type of new blast furnace, from suspended material identification and graded treatment to safe recovery, resulting in the handling process relying on personal experience, which introduces uncertainty and safety risks. Summary of the Invention

[0003] The purpose of this invention is to provide a method for diagnosing, treating and restoring hydrogen-rich carbon-circulating oxygen blast furnace suspended materials, in order to solve the problems of non-standardized operation, difficulty in coordinated control of multiple gas media, lack of safety interlock management and unstable recovery process in traditional methods when dealing with such blast furnace suspended materials.

[0004] To achieve the above objectives, the basic solution provided by this invention is: a method for diagnosing, treating, and restoring suspended burden in a hydrogen-rich carbon-circulating oxygen blast furnace, wherein the blast furnace has a volume of 2500 m³. 3 And above, including: the following steps to be performed sequentially: Suspension confirmation and initial response steps include confirming the occurrence of suspension and canceling the gas outage interlock function; System reduction and safety precautions include stopping the delivery of natural gas and pulverized coal, and opening the vent inspection port to supply nitrogen to the preset flow rate; The parameter grading fine adjustment steps include reducing oxygen flow and decarbonized gas flow in two stages while simultaneously reducing blast furnace top pressure. When the decarbonized gas flow is reduced to the first preset range, the oxygen flow is reduced to the second preset range and the pressure difference between oxygen and decarbonized gas is controlled to a preset value. When the decarbonized gas flow is lower than the first threshold, a linkage mechanism is established between the reduction of decarbonized gas flow and the increase of gas safety nitrogen flow. When the oxygen flow is reduced to the second threshold, the oxygen safety nitrogen is activated. Emergency response procedures for extreme situations shall be implemented if the suspension of material is still not relieved after the parameter grading and fine adjustment steps, including stopping oxygen supply and performing a material setting operation, while converting the blast furnace top pressure to atmospheric pressure. The system recovery and production restart steps are executed after the suspension is lifted, including gradually increasing the flow rates of decarbonized gas and oxygen, while simultaneously reducing the flow rates of gas safety nitrogen and oxygen safety nitrogen. When the flow rate of decarbonized gas recovers to the third threshold, the gas shutdown interlock function is activated and natural gas transmission is restored.

[0005] Furthermore, in the parameter grading fine adjustment step, the step of reducing the oxygen flow rate and decarbonized gas flow rate in two stages includes: performing a first-stage adjustment to reduce the oxygen flow rate by a first preset value, and then reducing the decarbonized gas flow rate by a second preset value; if the air pressure does not decrease and the pressure difference does not decrease after the first-stage adjustment, then performing a second-stage adjustment to reduce the oxygen flow rate by a third preset value, and then reducing the decarbonized gas flow rate by a fourth preset value, wherein the third preset value is greater than the first preset value.

[0006] Furthermore, the second-level adjustment also includes raising all the probes of the blast furnace before execution.

[0007] Furthermore, the first preset range is 90000 Nm. 3 / h to 100000Nm 3 / h, the second preset range is 16000 Nm 3 / h to 18000Nm 3 / h, the preset value of the pressure difference between the oxygen and the decarbonized coal gas is 0.08MPa.

[0008] Furthermore, the first threshold is 90000 Nm 3 / h, the linkage mechanism is as follows: for every 20000 Nm³ decrease in decarbonized gas flow rate... 3 / h, then simultaneously increase the nitrogen flow rate for gas safety by 10000Nm 3 / h.

[0009] Furthermore, the second threshold is 16000 Nm 3 / h, the oxygen safety nitrogen flow rate is controlled at 3000 Nm 3 / h to 5000Nm 3 / h; the third threshold is 60000Nm 3 / h.

[0010] Furthermore, in the system recovery and production restart steps, gradually increasing the decarbonized gas flow rate includes: first increasing the decarbonized gas flow rate to 50,000 Nm³. 3 / h, and proportionally reduce the nitrogen flow rate for gas safety during this process.

[0011] Furthermore, in the system recovery and production restart steps, when the oxygen flow rate increases to 20000 Nm³... 3 When the oxygen and nitrogen injection reaches / h, stop the injection of oxygen and nitrogen for safety.

[0012] Furthermore, the method also includes a safety accident emergency response procedure parallel to the handling of suspended material, which includes: fully opening the safety nitrogen supply to the decarburized gas injection pipeline and stopping the decarburized gas injection; fully opening the safety nitrogen supply to the oxygen injection pipeline and stopping the oxygen injection; adjusting the blast furnace top pressure setpoint to atmospheric pressure and locking it; gradually reducing the nitrogen purging volume of the gas system and oxygen system according to the on-site situation; implementing the pressure reduction and blast shutdown procedure after the on-site situation is under control; and immediately evacuating all personnel in the tapping area during the handling of the tuyeres burn-through accident.

[0013] Furthermore, the method also includes placing the gas injection system and the oxygen injection system into automatic operation mode under normal production conditions without accidents.

[0014] Compared with the prior art, the advantages of this invention are: This invention reduces reliance on individual experience by breaking down the suspended charge handling process into a logically clear and standardized operating procedure. Through orderly, coordinated, and precise linkage adjustment of various gas media and pressure parameters, specific flow thresholds and differential pressure standards are set, achieving refined operation. This effectively disrupts the mechanical balance of the suspended charge while preventing drastic furnace temperature changes. A multi-layered, comprehensive safety protection system is constructed, encompassing initial personnel evacuation, nitrogen protection through inspection holes during the handling process, timely intervention of safety nitrogen, and cautious implementation of interlocking functions during the recovery phase. The phased and sequential gas recovery mechanism ensures a smooth and rapid transition of the blast furnace from an accident state to normal production, thereby minimizing unplanned shutdown time and reducing production losses. Detailed Implementation

[0015] The present invention will be further described in detail below through specific embodiments: This invention provides a basic process for the diagnosis, treatment, and recovery of suspended burden in a hydrogen-rich carbon-circulating oxygen blast furnace. This method is applied to blast furnaces with a volume of 2500m³. 3The system is a hydrogen-rich carbon-circulating oxygen blast furnace. It includes a central control system, an oxygen injection system, a decarbonized gas injection system, a natural gas injection system, a pulverized coal injection system, a nitrogen safety system, and a probe detection system. All systems are connected to the central control system via an industrial bus, and are monitored and operated centrally by the foreman in the control room.

[0016] The specific steps are as follows: During the suspension confirmation and initial response phase, the foreman monitored the air pressure, which abnormally increased from the normal value of 350 kPa to 420 kPa, and the two probes showed that the material level had not dropped within 30 minutes, confirming that suspension had occurred. After confirmation, the foreman clicked the "Cancel Gas Stop Interlock" function button on the HMI interface of the control system to release the system's automatic protection restrictions. At the same time, he inquired with the furnace foreman via walkie-talkie to confirm that the molten iron for this furnace had been completely poured out and that conditions were met for charging.

[0017] During the system reduction and safety precautions phase, the foreman immediately notified the personnel in charge of the decarbonization gas system to significantly reduce the degassing volume and lower the top pressure of the decarbonization blast furnace. Simultaneously, the following operations were performed: natural gas delivery was stopped, and pulverized coal injection was halted. The water watcher was instructed to open the nitrogen valves at half flow rate through the inspection holes of all 30 tuyeres in the blast furnace. This operation both cools the tuyeres to prevent burn-out and creates a localized gas curtain to improve safety. During this period, except for essential operators, all other personnel should stay away from the tuyeres platform.

[0018] In the parameter grading and fine-tuning stage, the first-level adjustment is performed: the oxygen flow rate is reduced from 43000 Nm³. 3 / h reduce 3000Nm 3 / h to 40000Nm 3 / h, then the decarbonized gas flow rate was reduced from 220000 Nm³. 3 / h reduction of 10000 Nm 3 / h to 210000Nm 3 At the same time, reduce the blast furnace top pressure from 195 kPa to 185 kPa by 10 kPa. After observing for 5 minutes, if the blast pressure remains at a high level of 415 kPa and the pressure difference does not improve, the first-stage adjustment is deemed ineffective, and the second-stage adjustment is executed: instruct the batching station to raise both probes, and then reduce the oxygen flow rate from 40000 Nm³ / h. 3 / h reduction of 5000 Nm 3 / h to 35000Nm 3 / h, decarbonized coal gas from 210000 Nm 3 / h reduction of 10000 Nm 3 / h to 200000Nm 3 / h, the top pressure is reduced by 10kPa to 175kPa.

[0019] When the decarbonized gas flow rate is gradually reduced to 95000 Nm3 At a flow rate of / h, the fine control phase begins. At this point, the oxygen flow rate is reduced to 17000 Nm³. 3 The pressure difference between oxygen and decarbonized gas is controlled at 0.08 MPa per hour. Maintaining this pressure difference ensures reasonable injection power, which can effectively disrupt the mechanical balance formed by the suspended material and avoid drastic fluctuations in furnace temperature.

[0020] When the decarbonized gas flow rate is further reduced to 85000 Nm 3 When the flow rate decreases by 20,000 Nm³ / h, the nitrogen safety intervention mechanism is activated. A linkage control system is established between the decarbonized gas and the nitrogen safety system: for every 20,000 Nm³ / h decrease in decarbonized gas flow rate... 3 / h, the system automatically and synchronously increases the nitrogen flow rate for gas safety by 10000 Nm. 3 / h. For example, when decarbonized gas is produced from 85000 Nm³. 3 / h reduced to 65000Nm 3 At a rate of / h, the nitrogen supply for gas safety protection will increase by 10000 Nm. 3 / h. When the oxygen flow rate is reduced to 16000 Nm 3 At a rate of / h, manually activate the oxygen safety nitrogen supply, controlling the flow rate at 4000 Nm³. 3 / h, and simultaneously reduce the blast furnace top pressure. This linkage mechanism effectively maintains pipeline safety and system pressure balance.

[0021] In extreme emergency response, if the suspended charge remains after the aforementioned fine-tuning, and the decarbonization gas has nearly stopped, with the blast pressure continuing to rise to 450 kPa, the final response measures should be implemented. Continue reducing the oxygen flow until it is completely stopped, and perform forced charging. If conditions permit, open the taphole and try to remove all slag and iron from the furnace to facilitate the collapse of the charge column. The operating sequence must be strictly followed: first stop the oxygen, then gradually reduce the nitrogen. Simultaneously, reduce the blast furnace top pressure to atmospheric pressure (approximately 10-20 kPa).

[0022] From the above emergency response procedures for extreme situations, it is clear that the timing of the charging operation is crucial. The optimal time for the charging operation is immediately after oxygen has completely stopped, at which point the reaction intensity inside the furnace is lowest, and the effect of the charge column collapsing under its own weight is most significant. The charging operation, by momentarily stopping the blast, causes the furnace charge to collapse under gravity, thereby relieving the suspended state.

[0023] During the system recovery and production restart phase, after the suspended material issue has been resolved and the furnace condition has stabilized, the system recovery procedure is executed. First, the decarbonization station is notified to begin increasing gas supply and re-feeding pulverized coal. The decarbonization gas flow rate is gradually increased to 50,000 Nm³. 3 / h, during this process, the system automatically reduces the flow rate of nitrogen gas introduced for safety during the emergency response phase proportionally. When the oxygen flow rate is increased to 20000 Nm³ / h... 3When the oxygen and nitrogen injection is at a certain time (h), shut off the oxygen and nitrogen injection for safety. All gas adjustment operations must simultaneously increase the blast furnace top pressure to maintain system pressure balance.

[0024] When the decarbonized gas flow rate increases to 65000 Nm 3 At 12:00 AM, the foreman activates the "gas stop interlock" function in the control system, restoring the system's automatic protection. Subsequently, the decarbonization team is notified to resume natural gas supply. The entire restoration process takes approximately 2 hours, during which all blast furnace parameters are closely monitored to ensure a smooth transition to normal production.

[0025] This invention also includes emergency response procedures for safety accidents that are handled concurrently with the handling of suspended materials. These procedures are applicable to emergencies such as tuyeres burn-through, furnace-front accidents, and external accidents that occur during normal blast furnace production. The standard operating sequence is as follows: First, fully open the safety nitrogen supply to the decarburized gas injection pipeline, then immediately stop the decarburized gas injection; next, fully open the safety nitrogen supply to the oxygen injection pipeline, then stop the oxygen injection; simultaneously, adjust the blast furnace top pressure setpoint to atmospheric pressure and lock it; depending on the specific situation on site, gradually reduce the nitrogen purging rate of the gas and oxygen systems; once the situation is completely under control, execute the pressure reduction and shutdown procedure for handling.

[0026] It is important to note that during the handling of a tuyer burn-through accident, all personnel in the tapping area must be evacuated immediately and unconditionally. Entry will only be permitted after the situation is under control and instructions have been followed. This safety measure effectively ensured personnel safety and prevented secondary accidents.

[0027] In the best practice mode, this invention also includes a normal operation mode setting. Under normal production conditions without accidents, the gas injection system and oxygen injection system should be placed in automatic operation mode to ensure that all safety interlock functions are in effective condition. This setting constitutes the first line of defense against accidents, effectively reducing the probability of process failures such as material suspension through automatic system monitoring and adjustment.

[0028] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for diagnosing, treating, and restoring suspended burden in a hydrogen-rich carbon-circulating oxygen blast furnace, wherein the blast furnace has a volume of 2500 m³. 3 and above, characterized in that, include: The following steps are performed sequentially: Suspension confirmation and initial response steps include confirming the occurrence of suspension and canceling the gas outage interlock function; System reduction and safety precautions include stopping the delivery of natural gas and pulverized coal, and opening the vent inspection port to supply nitrogen to the preset flow rate; The parameter grading fine adjustment steps include reducing oxygen flow and decarbonized gas flow in two stages while simultaneously reducing blast furnace top pressure. When the decarbonized gas flow is reduced to the first preset range, the oxygen flow is reduced to the second preset range and the pressure difference between oxygen and decarbonized gas is controlled to a preset value. When the decarbonized gas flow is lower than the first threshold, a linkage mechanism is established between the reduction of decarbonized gas flow and the increase of gas safety nitrogen flow. When the oxygen flow is reduced to the second threshold, the oxygen safety nitrogen is activated. Emergency response procedures for extreme situations shall be implemented if the suspension is still not relieved after the parameter grading and fine adjustment steps, including stopping oxygen supply and performing a charging operation, while converting the blast furnace top pressure to atmospheric pressure. The system recovery and production restart steps are executed after the suspension is lifted, including gradually increasing the flow rates of decarbonized gas and oxygen, while simultaneously reducing the flow rates of gas safety nitrogen and oxygen safety nitrogen. When the flow rate of decarbonized gas recovers to the third threshold, the gas shutdown interlock function is activated and natural gas transmission is restored.

2. The method for diagnosing, treating, and restoring suspended burden in a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 1, characterized in that, In the parameter grading fine adjustment step, the step of reducing the oxygen flow rate and decarbonized gas flow rate in two stages includes: performing the first stage adjustment, reducing the oxygen flow rate by a first preset value, and then reducing the decarbonized gas flow rate by a second preset value; if the air pressure does not decrease and the pressure difference does not decrease after the first stage adjustment, then performing the second stage adjustment, reducing the oxygen flow rate by a third preset value, and then reducing the decarbonized gas flow rate by a fourth preset value, wherein the third preset value is greater than the first preset value.

3. The method for diagnosing, treating, and restoring suspended burden in a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 2, characterized in that, The second-level adjustment also includes raising all the probes of the blast furnace before it is executed.

4. The method for diagnosing, treating, and restoring suspended burden in a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 1, characterized in that, The first preset range is 90000 Nm 3 / h to 100000Nm 3 / h, the second preset range is 16000 Nm 3 / h to 18000Nm 3 / h, the preset value of the pressure difference between the oxygen and the decarbonized coal gas is 0.08MPa.

5. The method for diagnosing, treating, and restoring suspended burden in a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 1, characterized in that, The first threshold is 90000 Nm 3 / h, the linkage mechanism is as follows: for every 20000 Nm³ decrease in decarbonized gas flow rate... 3 / h, then simultaneously increase the nitrogen flow rate for gas safety by 10000Nm 3 / h.

6. The method for diagnosing, treating, and restoring suspended burden in a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 1, characterized in that, The second threshold is 16000 Nm 3 / h, the oxygen safety nitrogen flow rate is controlled at 3000 Nm 3 / h to 5000Nm 3 / h; the third threshold is 60000Nm 3 / h.

7. The method for diagnosing, treating, and restoring suspended burden in a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 1, characterized in that, The system recovery and production restart steps, including gradually increasing the decarbonized gas flow rate, include: first increasing the decarbonized gas flow rate to 50,000 Nm³. 3 / h, and proportionally reduce the nitrogen flow rate for gas safety during this process.

8. The method for diagnosing, treating, and restoring suspended burden in a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 1, characterized in that, During the system recovery and production restart steps, when the oxygen flow rate increases to 20000 Nm³, 3 When the oxygen and nitrogen injection reaches / h, stop the injection of oxygen and nitrogen for safety.

9. The method for diagnosing, treating, and restoring suspended burden in a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 1, characterized in that, The method also includes a safety accident emergency response procedure that runs parallel to the suspended material handling process. This procedure includes: fully opening the safety nitrogen supply to the decarburized gas injection pipeline and stopping the decarburized gas injection; fully opening the safety nitrogen supply to the oxygen injection pipeline and stopping the oxygen injection; adjusting the blast furnace top pressure setpoint to atmospheric pressure and locking it; gradually reducing the nitrogen purging volume of the gas system and oxygen system according to the on-site situation; implementing the pressure reduction and blast shutdown procedure after the on-site situation is under control; and immediately evacuating all personnel in the tapping area during the handling of the tuyeres burn-through accident.

10. The method for diagnosing, treating, and restoring suspended burden in a hydrogen-rich carbon-circulating oxygen blast furnace according to claim 1, characterized in that, The method also includes setting the gas injection system and the oxygen injection system to automatic operation mode under normal production conditions without accidents.