A safety control method for blast furnace top pressure

Abstract

The application discloses a safety control method for blast furnace top pressure, which adjusts the blast furnace top pressure in three stages, and adjusts the blast furnace top pressure in different stages through a pressure regulating valve, a blast furnace blower, and a blast furnace blower and a blast furnace diffuser valve. The safety control method for blast furnace top pressure adjusts the blast furnace top pressure in three stages in combination with the characteristics of each adjusting path, and when adjusting each stage, not only the problem of blast furnace top pressure pressure reduction is considered, but also the problem of blast furnace production is considered, the blast furnace top pressure is finely controlled from two aspects of blast furnace top pressure pressure reduction and blast furnace production, so that the production efficiency of the blast furnace is maximally ensured under the premise that the blast furnace top pressure is safe and controllable, and the overall production of the blast furnace is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of ironmaking blast furnaces, and in particular to a method for safely controlling blast furnace top pressure. Background Art

[0002] During the blast furnace smelting process, hot air must be introduced to the blast furnace to promote the reaction of iron ore within the furnace. This reaction produces large amounts of CO, CO₂, H₂, and N₂ gases (collectively referred to as blast furnace gas), which also need to be exhausted. To recover and reuse blast furnace energy during this process, a blast furnace power recovery turbine (BPRT) is often installed. A BPRT unit integrates the gas turbine and blast furnace blower as a single system. Specifically, after the blast furnace gas is exhausted, it passes through gravity dust removal and dry purification equipment before being fed into the gas turbine, where it undergoes energy conversion. The energy recovered by the gas turbine is then used to power the blast furnace blower, providing power for the hot air supply.

[0003] Maintaining stable blast furnace top pressure (referred to as top pressure) is one of the key measures for ensuring stable blast furnace production. To regulate the pressure when it's too high, the aforementioned blast furnace system includes a pressure-regulating valve installed on a branch pipe leading from the blast furnace gas pipeline between the purification unit and the gas turbine, and a relief valve installed on the blast furnace top. When the blast furnace top pressure is too high, the current practice is to rely solely on the pressure-regulating valve for small pressure increases. In this case, the blast furnace remains fully depressurized and operation can continue. When the pressure increases significantly, the regulating valve is fully opened, or the relief valve is directly opened. This causes the blast furnace to lose pressure and cease operation.

[0004] Under the above adjustment method, the adjustment path is extremely limited. On the one hand, before the control valve is fully opened or the relief valve is opened and the blast furnace loses pressure and stops working, only the pressure regulating valve can be relied on for adjustment alone. Only in this way can the blast furnace continue to work without complete pressure loss, which has too high dependence on the pressure regulating valve. This requires the pressure regulating valve to operate normally at all times and there should be no abnormal situation at the front end of the pressure regulating valve. Once the pressure regulating valve is abnormal or there is a fault at the front end of the pressure regulating valve, such as the shut-off valve at the inlet of gravity dust removal drops and closes due to the fracture of the steel wire rope, or the automatic valve at the inlet and outlet of the dry purification device closes abnormally, the adjustment function of the pressure regulating valve will completely fail, and the top pressure of the blast furnace is likely to continue to rise, and the relief valve has to be opened, resulting in the blast furnace losing pressure and stopping working. Even the relief valve may not be opened in time, causing a blast furnace explosion accident. On the other hand, under the limited adjustment path, the adjustment refinement degree is relatively low. When the top pressure of the blast furnace continues to rise under the adjustment of the control valve, only the control valve can be fully opened or the relief valve can be opened, resulting in the blast furnace losing pressure and shutting down. The simple top pressure adjustment is likely to affect the production efficiency of the blast furnace. Summary of the Invention

[0005] The purpose of the present invention is to provide a safety control method for the top pressure of a blast furnace.

[0006] The technical solution for achieving the purpose of the present invention is: a safety control method for the top pressure of a blast furnace, which is applied to a blast furnace system and includes the following steps:

[0007] S1. Set a pressure measuring point for monitoring the top pressure in the blast furnace, and monitor the top pressure N in real time through the pressure measuring point;

[0008] S2. Set normal pressure parameter M1, high pressure parameter M2 and ultra-high pressure parameter M3. M1, M2 and M3 are all non-negative numbers, and M1 < M2 < M3;

[0009] S3. According to the top pressure N monitored by the pressure measuring point, judge the top pressure situation of the blast furnace and conduct hierarchical control; specifically:

[0010] S3.1. When N < M1, judge that the top pressure of the blast furnace is normal and no adjustment is required;

[0011] S3.2. When M1 ≤ N < M2, judge that the top pressure of the blast furnace is slightly high. At this time, trigger a first-level alarm, and at the same time, control the pressure regulating valve to adjust the top pressure of the blast furnace through the pressure regulating valve; <00000​​​​S3.3. When M2 ≤ N < M3, it is judged that the top pressure of the blast furnace is medium-high. At this time, a secondary alarm is triggered. Meanwhile, the blast furnace blower is controlled to reduce the air volume of the blast furnace blower once.

[0014] After the air volume of the blast furnace blower is reduced once, if the top pressure N drops to M1 ≤ N < M2, the control of reducing the air volume of the blast furnace blower is stopped, and the blast furnace blower resumes normal operation and returns to step S3.2; if the top pressure N continues to rise, step S3.4 is performed.

[0015] S3.4. When N ≥ M3, it is judged that the top pressure of the blast furnace is too high. At this time, a tertiary alarm is triggered, the blast furnace blower is controlled to reduce the air volume of the blast furnace blower twice, and meanwhile, the blast furnace relief valve is opened; after the air volume of the blast furnace blower is reduced twice, the air volume of the blast furnace blower is limited by the condition that the pressure of the hot blast stove is slightly greater than the pressure inside the blast furnace and a positive pressure can be formed in the direction from the hot blast stove to the blast furnace.

[0016] Furthermore, the pressure measuring point is located at the top of the blast furnace or in the gas pipeline that sequentially connects the gas outlet of the blast furnace, the gas dust removal and purification device, and the gas turbine. The pressure measuring point can be the measuring point of a pressure sensor or the measuring point of a flow sensor.

[0017] Furthermore, the number of the pressure measuring points is more than two, and the more than two pressure measuring points are located at different positions. With the setting of multiple pressure measuring points, when judging the top pressure condition of the blast furnace and performing hierarchical control, it can be judged by relying on a part of the top pressure N. For example, when three pressure measuring points measure three top pressure N values, one value or two values can be selected from the three top pressure N values for comparison and judgment; or the average value of all the top pressure N can be taken for comparison and judgment. Compared with a single pressure measuring point, multiple pressure measuring points can not only measure the top pressure N, but also judge and analyze whether each pressure measuring point is damaged and accurate through the measured top pressure N. And once a pressure measuring point is damaged, other pressure measuring points can also be replaced online for use.

[0018] Furthermore, the number of pressure measuring points is multiple, and the multiple pressure measuring points are divided into two or more groups, wherein a first group of pressure measuring points is located at the front end of the gas dust removal and purification device, and a second group of pressure measuring points is located at the rear end of the gas dust removal and purification device. The first group of pressure measuring points, the gas dust removal and purification device, the second group of pressure measuring points, and the gas turbine are sequentially distributed along the gas path. The first group of pressure measuring points located at the front end of the gas dust removal and purification device can be located at the top of the blast furnace or within the gas pipeline between the blast furnace and the gas dust removal and purification device; the second group of pressure measuring points located at the rear end of the gas dust removal and purification device are located within the gas pipeline between the gas dust removal and purification device and the gas turbine. When the pressure measuring points are provided at the front and rear ends of the gas dust removal and purification device, not only the top pressure N can be measured through the pressure measuring points provided at the front and rear ends, but also the valves of the gas dust removal and purification devices can be judged and analyzed based on the measured top pressures N. For example, if the top pressure N measured by the first group of pressure measuring points is very large and the top pressure N measured by the second group of pressure measuring points is very small, it means that the valves of the gas dust removal and purification device are easily closed.

[0019] Furthermore, the coal gas dust removal and purification device includes a gravity dust removal device and a dry purification device arranged in sequence along the coal gas path. The number of the pressure measuring points is several, and the several pressure measuring points are divided into three groups, wherein the first group of pressure measuring points is located at the front end of the gravity dust removal device, the second group of pressure measuring points is located at the rear end of the dry purification device, and the third group of pressure measuring points is located between the gravity dust removal device and the dry purification device. The first group of pressure measuring points, the gravity dust removal device, the third group of pressure measuring points, the dry purification device, the second group of pressure measuring points, and the coal gas turbine are distributed in sequence along the coal gas path. The first group of pressure measuring points located at the front end of the gravity dust removal device can be located at the top of the blast furnace or in the coal gas pipeline between the blast furnace and the gravity dust removal device; the second group of pressure measuring points located at the rear end of the dry purification device is located in the coal gas pipeline between the coal gas dust removal and purification device and the coal gas turbine; and the third group of pressure measuring points is located in the coal gas pipeline between the gravity dust removal device and the dry purification device. After multiple dust removal and purification by the gravity dust removal device and the dry purification device, the purity of the coal gas is higher. When the coal gas dust removal and purification device includes the gravity dust removal device and the dry purification device, the three groups of pressure measuring points set can not only measure the top pressure N, but also judge and analyze whether the valves of the gravity dust removal device and the dry purification device are easy to close through each measured top pressure N. If the top pressure N measured by the first group of pressure measuring points is very large, and the top pressure N measured by the second group of pressure measuring points and the top pressure N measured by the third group of pressure measuring points are very small, then it means that the valve of the gravity dust removal device is easy to close; if the top pressure N measured by the first group of pressure measuring points and the top pressure N measured by the third group of pressure measuring points are very large, and the top pressure N measured by the second group of pressure measuring points is very small, then it means that the valve of the dry purification device is easy to close.

[0020] Furthermore, the range of the atmospheric pressure parameter M1 is 204-206 kPa. Preferably, the atmospheric pressure parameter M1 is 205 kPa. During normal production of a blast furnace, the top pressure is usually around 205 kPa.

[0021] Furthermore, the high pressure parameter M2 has a value range of 209-211 kPa. Preferably, the normal pressure parameter M2 is 210 kPa.

[0022] Furthermore, the ultrahigh pressure parameter M3 is in the range of 214-216 kPa. Preferably, the normal pressure parameter M2 is 215 kPa. The maximum pressure resistance of a blast furnace is generally around 215 kPa.

[0023] Furthermore, in step S3.3, the blast furnace blower reduces air pressure by 45-55 kPa at a time. Preferably, the blast furnace blower reduces air pressure by 50 kPa at a time. During normal blast furnace operation, the top pressure is typically around 205 kPa, and the maximum withstand pressure of a blast furnace is typically around 215 kPa. By reducing the air pressure by 45-55 kPa at a time, the top pressure in the blast furnace can be significantly adjusted.

[0024] Furthermore, in step S3.4, the blast furnace blower is reduced to 25-35KPa for a second time. Preferably, the blast furnace blower is reduced to 30KPa for a second time. Under the third-level alarm, after the blast furnace vent valve is opened, the blast furnace can quickly lose pressure to prevent explosion and stop working. However, the blast furnace after decompression is not completely pressure-free, but still has a certain pressure. In this case, the blast furnace blower is reduced to 25-35KPa for a second time, but not completely shut down. The purpose is to ensure that the hot blast furnace can have a minimum air volume. This small air volume can form a positive pressure from the hot blast furnace to the blast furnace without affecting the pressure relief of the blast furnace, so as to prevent the blast furnace from pouring slag into the hot blast furnace.

[0025] The safety control method for blast furnace top pressure of the present invention, in addition to the adjustment path of the pressure regulating valve and the blast furnace bleed valve, adds an adjustment path for reducing the air flow of the blast furnace blower. Compared with the traditional top pressure control method with only a pressure regulating valve and a bleed valve, on the one hand, the present application includes more adjustment paths for the pressure regulating valve, the blast furnace bleed valve and the blast furnace blower. With more adjustment paths, the adjustment paths are more selective, more flexible, and more conducive to refined control; on the other hand, after adding the adjustment path for reducing the air flow of the blast furnace blower, since the blast furnace blower is not only located at the blast furnace air inlet end, but also the source of the blast furnace top pressure, when the source of the blast furnace top pressure is controlled by the blast furnace blower, the blast furnace top pressure can be fundamentally changed, and the adjustment and control of the blast furnace top pressure is more effective and efficient.

[0026] The safety control method for blast furnace top pressure of the present invention, after developing three ways to adjust blast furnace top pressure, regulates the blast furnace top pressure in three stages. Compared with the traditional simple and crude two-stage regulation method using only a pressure regulating valve and a relief valve, the regulation accuracy is higher and the changes in each top pressure can be more accurately controlled. For example, when the blast furnace is at a high level, the relief valve is directly opened to relieve the pressure and prevent explosion. However, in the safety control method for blast furnace top pressure of the present invention, when the blast furnace is at a high level, the blast furnace blower is first used to reduce the air flow to adjust the blast furnace top pressure. After the blast furnace blower is adjusted, the blast furnace top pressure drops and no longer rises, and the relief valve is not directly opened. Precisely because of this more accurate control, the blast furnace production efficiency of the present invention can be higher, and the frequency of shutdowns due to pressure loss when the relief valve is opened is reduced.

[0027] As mentioned above, the blast furnace blower is located at the air inlet end of the blast furnace. The control of the source of the blast furnace top pressure by the blast furnace blower belongs to the regulation of the source of the blast furnace top pressure. The regulation effect of the blast furnace blower is more significant than the regulation effect of the pressure regulating valve; but when the blast furnace blower is adjusted, the hot air in the blast furnace is reduced, the reaction in the blast furnace is affected, and the working efficiency of the blast furnace is reduced. The pressure regulating valve is located at the rear end of the blast furnace. When the pressure regulating valve is adjusted, the working efficiency in the blast furnace is not affected. That is to say, compared with the blast furnace blower, adjusting the pressure regulating valve has less impact on the operation of the blast furnace. The safety control method for blast furnace top pressure of the present invention regulates the blast furnace top pressure in three stages. In combination with the characteristics of the above-mentioned regulating paths, when the top pressure of the blast furnace is slightly high or a level one alarm is issued, the regulating demand for the top pressure of the blast furnace is small and the urgency of regulation is low. At this time, regulation is performed through the pressure regulating valve. Although the regulating effect of the pressure regulating valve is not as good as that of the blast furnace blower, for the level one alarm of slightly high top pressure, the pressure regulating valve basically meets its regulating demand and will not affect the operation of the blast furnace, so that the blast furnace can still maintain efficient production. When the top pressure of the blast furnace is medium-high or a level two alarm is issued, the regulating demand for the top pressure of the blast furnace is large and the regulation is more urgent. At this time, on the basis of the regulation of the pressure regulating valve, the blast furnace blower is further reduced to control the blast furnace air intake from the source. After the air volume is controlled at the source, although the reaction in the blast furnace is slightly affected, the blast furnace top pressure can be rapidly reduced. The efficiency of top pressure regulation is greatly improved, so that the current urgent blast furnace top pressure can be alleviated; when the top pressure of the blast furnace is too high and the third level alarm is set, the regulation demand of the blast furnace top pressure reaches the limit, and the blast furnace is in a relatively dangerous situation. At this time, in addition to the traditional method of directly opening the blast furnace vent valve, the blast furnace blower is also controlled to further reduce the air for a second time. The blast furnace vent valve quickly discharges the coal gas from the rear end of the blast furnace, and the blast furnace blower reduces the blast furnace air intake from the front end of the blast furnace. On the basis of the pressure regulating valve, the dual combination of the blast furnace vent valve and the blast furnace blower can be dual-controlled from the front and rear ends of the blast furnace to vent and relieve the pressure of the blast furnace. Compared with the traditional single-mode venting by opening the vent valve from the rear end of the blast furnace, the dual-controlled venting and pressure relief of the present invention is faster and more efficient in relieving high-pressure dangers. In other words, it is more secure in the case of high-pressure dangers and has better production safety.

[0028] The safety control method for blast furnace top pressure of the present invention combines the characteristics of various adjustment paths and adjusts the blast furnace top pressure in three stages. When adjusting each stage, not only the problem of blast furnace top pressure reduction but also the problem of blast furnace production are taken into consideration. From the two aspects of blast furnace top pressure reduction and blast furnace production, the blast furnace top pressure is precisely controlled in a targeted manner, so that under the premise of safe and controllable blast furnace top pressure, the production efficiency of the blast furnace is guaranteed to the greatest extent, thereby ensuring the overall production of the blast furnace.

[0029] In addition, in the safety control method for the top pressure of the blast furnace of the present invention, when the top pressure of the blast furnace is too high and the blast furnace blower is further controlled to reduce the air volume for the second time, the air volume of the blast furnace blower is reduced to the minimum value that can form a positive pressure in the direction from the hot blast stove to the blast furnace. This setting controls the air volume of the blast furnace blower at the minimum value on the premise of preventing the blast furnace from pouring slag into the hot blast stove, enabling the blast furnace to quickly discharge, preventing the blast furnace from exploding under high pressure, and protecting the blast furnace from pouring slag into the hot blast stove, reducing the faults of the hot blast stove. That is to say, the present invention takes into account both the hot blast stove and the blast furnace, and controls the top pressure of the blast furnace as a whole. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic structural diagram of the blast furnace system in the safety control method for the top pressure of the blast furnace of the present invention;

[0031] Figure 2 is a flowchart of the safety control method for the top pressure of the blast furnace of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The following is a detailed description of the preferred embodiments of the safety control method for the top pressure of the blast furnace of the present invention in conjunction with the accompanying drawings:

[0033] As Figure 1 and Figure 2 shown, a safety control method for the top pressure of a blast furnace includes the following steps:

[0034] S1. Set a pressure measuring point 8 for monitoring the top pressure in the blast furnace 1, and monitor the top pressure N in real time through the pressure measuring point 8;

[0035] S2. Set normal pressure parameter M1, high pressure parameter M2, and ultra-high pressure parameter M3. M1, M2, and M3 are all non-negative numbers, and M1 < M2 < M3;

[0036] S3. According to the top pressure N monitored by the pressure measuring point 8, judge the top pressure situation of the blast furnace 1 and perform hierarchical control; specifically:

[0037] S3.1. When N < M1, judge that the top pressure of the blast furnace 1 is normal and no adjustment is required;

[0038] S3.2. When M1 ≤ N < M2, judge that the top pressure of the blast furnace 1 is slightly high. At this time, trigger a first-level alarm, and at the same time, control the pressure regulating valve 6 to adjust the top pressure of the blast furnace through the pressure regulating valve 6;

[0039] After the adjustment through the pressure regulating valve 6, if the top pressure N drops to N < M1, stop controlling the pressure regulating valve 6 and return to step S3.1; if the top pressure N continues to rise, then perform step S3.3;

[0040] S3.3. When M2 ≤ N < M3, it is judged that the top pressure of the blast furnace 1 is medium-high. At this time, a secondary alarm is triggered. Meanwhile, the blast furnace blower 32 is controlled to reduce the air volume of the blast furnace blower 32 once.

[0041] After the blast furnace blower 32 reduces the air volume once, if the top pressure N drops to M1 ≤ N < M2, the control of reducing the air volume of the blast furnace blower 32 is stopped, and the blast furnace blower 32 resumes normal operation and returns to step S3.2; if the top pressure N continues to rise, step S3.4 is performed.

[0042] S3.4. When N ≥ M3, it is judged that the top pressure of the blast furnace 1 is too high. At this time, a tertiary alarm is triggered, and the blast furnace blower 32 is controlled to reduce the air volume of the blast furnace blower 32 twice. Meanwhile, the blast furnace relief valve 7 is opened; after reducing the air volume twice, the air volume of the blast furnace blower 32 is limited by the condition that the pressure of the hot blast stove 4 is slightly greater than the pressure inside the blast furnace 1 and a positive pressure can be formed in the direction from the hot blast stove 4 to the blast furnace 1.

[0043] The safety control method for the top pressure of the blast furnace in the present invention is applied to a blast furnace system. The blast furnace system includes a blast furnace 1, a gas dust removal and purification device 2, a BPRT unit 3, and a hot blast stove 4. The blast furnace 1 has a hot blast tuyere 11 and a gas port 12. The BPRT unit 3 includes a gas turbine 31 and a blast furnace blower 32. The blast furnace blower 32, the hot blast stove 4, and the hot blast tuyere 11 of the blast furnace 1 are connected in sequence. The gas port 12 of the blast furnace 1, the gas dust removal and purification device 2, and the gas turbine 31 are connected in sequence through a gas pipeline 51. The gas turbine 31 is connected to the blast furnace blower 32 and provides energy for the blast furnace blower 32. A branch pipe 52 is connected to the gas pipeline 51 between the gas dust removal and purification device 2 and the gas turbine 31. A pressure regulating valve 6 is installed on the branch pipe 52. A blast furnace relief valve 7 is installed at the top of the blast furnace 1.

[0044] The safety control method for blast furnace top pressure of the present invention is applied in a blast furnace system, wherein the hot blast furnace 4 is burned to provide hot blast to the blast furnace 1; the blast furnace blower 32 is used to provide power for transporting hot blast from the hot blast furnace 4 to the blast furnace 1; the iron ore in the blast furnace 1 reacts to form coal gas; the coal gas dust removal and purification device 2 is used to remove dust and purify the coal gas output from the blast furnace 1. The BPRT unit 3 connects the coal gas turbine 31 and the blast furnace blower 32 into a system, which is mainly used for recycling energy in the coal gas; wherein the coal gas turbine 31 is used to convert the energy in the coal gas for recycling; after the coal gas turbine 31 recovers the energy in the coal gas, it is provided to the blast furnace blower 32 for reuse by the blast furnace blower 32. The pressure regulating valve 6 is mounted on the branch pipe 52. By proportionally opening and closing the pressure regulating valve 6, the output of the gas in the blast furnace 1 from the branch pipe 52 can be adjusted, thereby adjusting the top pressure of the blast furnace 1. The blast furnace relief valve 7 is directly mounted on the top of the blast furnace 1. When the blast furnace relief valve 7 is opened, the gas in the blast furnace 1 can be directly released through the blast furnace relief valve 7.

[0045] During operation of the blast furnace system, the hot blast furnace 4 burns, and under the power of the blast furnace blower 32, it continuously provides hot blast to the blast furnace 1, promoting the reaction of the iron ore within the blast furnace 1. The iron ore reaction within the blast furnace 1 generates a large amount of coal gas. This coal gas enters the coal gas pipeline 51 from the top of the blast furnace 1, then flows along the coal gas dust removal and purification device 2 along the coal gas pipeline 51, where it is dusted and purified by the coal gas dust removal and purification device 2. The coal gas, after being dusted and purified by the coal gas dust removal and purification device 2, is then sent along the coal gas pipeline 51 to the coal gas turbine 31, which converts and recovers the energy in the coal gas. The recovered energy is then provided to the blast furnace blower 32 for reuse.

[0046] The safety control method for the top pressure of the blast furnace in the present invention monitors the top pressure N of the blast furnace 1 in real time through the pressure measuring point 8, and based on the monitored top pressure N, judges the top pressure condition of the blast furnace 1 in real time and conducts hierarchical control. Before judgment, corresponding settings are made for the normal pressure parameter M1, the high pressure parameter M2, and the ultra-high pressure parameter M3 according to the daily working data of the blast furnace top pressure. Among them, when M1 ≤ N < M2, it is judged that the top pressure of the blast furnace 1 is slightly high. At this time, a first-level alarm is triggered, and the top pressure of the blast furnace is adjusted through the pressure regulating valve 6; when M2 ≤ N < M3, it is judged that the top pressure of the blast furnace 1 is medium-high. At this time, a second-level alarm is triggered. On the basis of adjusting the top pressure of the blast furnace by the pressure regulating valve 6 after the first-level alarm, the primary air reduction of the blast furnace blower 32 is also controlled; when N ≥ M3, it is judged that the top pressure of the blast furnace 1 is too high. At this time, a third-level alarm is triggered. On the basis of adjusting the top pressure of the blast furnace by the pressure regulating valve 6 after the first-level alarm and controlling the primary air reduction of the blast furnace blower 32 after the second-level alarm, the secondary air reduction of the blast furnace blower 32 is further controlled. After the secondary air reduction, the air volume of the blast furnace blower 32 is limited by the condition that the pressure of the hot blast stove 4 is slightly greater than the pressure inside the blast furnace 1 and a positive pressure can be formed in the direction from the hot blast stove 4 to the blast furnace 1. At the same time, the blast furnace relief valve 7 is opened.

[0047] In the safety control method for the top pressure of the blast furnace in the present invention, there are three adjustment ways for the top pressure of the blast furnace: the pressure regulating valve 6, the blast furnace relief valve 7, and the blast furnace blower 32. Among them, the adjustment ways of the pressure regulating valve 6 and the blast furnace relief valve 7 are located at the air outlet end of the blast furnace. By controlling the gas discharge flow rate at the air outlet end of the blast furnace, the adjustment and control of the top pressure of the blast furnace 1 are realized; the blast furnace blower 32, as the power for the blast furnace inlet air and the source of the top pressure of the blast furnace 1, is located at the blast furnace inlet end. By controlling the inlet air of the blast furnace, the adjustment and control of the top pressure of the blast furnace 1 are realized.

[0048] The safety control method for the top pressure of the blast furnace in the present invention adds an adjustment way of reducing the air volume of the blast furnace blower 32 in addition to the adjustment ways of the pressure regulating valve 6 and the blast furnace relief valve 7. Compared with the traditional top pressure control method with only a pressure regulating valve and a relief valve, on the one hand, the adjustment ways of the present application include the pressure regulating valve 6, the blast furnace relief valve 7, and the blast furnace blower 32, and there are more adjustment ways. With more adjustment ways, the selectivity of the adjustment ways is more, more flexible, and more conducive to refined control; on the other hand, after adding the adjustment way of reducing the air volume of the blast furnace blower 32, since the blast furnace blower 32 is not only located at the blast furnace inlet end but also the source of the top pressure of the blast furnace 1, when controlling the source of the blast furnace top pressure through the blast furnace blower 32, the top pressure of the blast furnace can be fundamentally changed, and the adjustment and control of the blast furnace top pressure are more effective and efficient.

[0049] The safety control method for blast furnace top pressure of the present invention, after developing three ways to adjust blast furnace top pressure, regulates the blast furnace top pressure in three stages. Compared to the traditional, simple, two-stage regulation method using only a pressure regulating valve and a relief valve, the regulation accuracy is higher and the changes in each top pressure can be more accurately controlled. For example, when the blast furnace is at a high pressure, the relief valve is directly opened to relieve the pressure and prevent explosion. However, in the safety control method for blast furnace top pressure of the present invention, when the blast furnace is at a high pressure, the blast furnace blower 32 is first used to reduce the air flow to adjust the blast furnace top pressure. After the blast furnace blower 32 is adjusted, the blast furnace top pressure drops and stops rising, and the relief valve is not directly opened. Precisely because of this more accurate control, the blast furnace production efficiency of the present invention can be higher, and the frequency of shutdowns due to pressure loss when the relief valve is opened is reduced.

[0050] As mentioned above, the blast furnace blower 32 is located at the air inlet end of the blast furnace. The control of the source of the blast furnace top pressure by the blast furnace blower 32 belongs to the regulation of the source of the top pressure of the blast furnace 1. The regulation effect of the blast furnace blower 32 is more significant than the regulation effect of the pressure regulating valve 6; but when the blast furnace blower 32 is adjusted, the hot air in the blast furnace 1 is reduced, the reaction in the blast furnace 1 is affected, and the working efficiency of the blast furnace 1 is reduced, while the pressure regulating valve 6 is located at the rear end of the blast furnace. When the pressure regulating valve 6 is adjusted, the working efficiency in the blast furnace 1 is not affected. That is to say, compared with the blast furnace blower 32, adjusting the pressure regulating valve 6 has less impact on the operation of the blast furnace 1. The safety control method for blast furnace top pressure of the present invention adjusts the blast furnace top pressure in three stages. Combined with the characteristics of the above-mentioned adjustment paths, when the top pressure of the blast furnace 1 is slightly high or at the first level alarm, the adjustment demand for the top pressure of the blast furnace 1 is small and the adjustment urgency is low. At this time, the adjustment is performed through the pressure regulating valve 6. Although the adjustment effect of the pressure regulating valve 6 is not as good as that of the blast furnace blower 32, for the first level alarm of slightly high top pressure, the pressure regulating valve 6 basically meets its adjustment demand and will not affect the operation of the blast furnace 1, so that the blast furnace 1 can still maintain efficient production; when the top pressure of the blast furnace 1 is medium-high or at the second level alarm, the adjustment demand for the top pressure of the blast furnace 1 is large and the adjustment is more urgent. At this time, on the basis of the adjustment of the pressure regulating valve 6, the blast furnace blower 32 is reduced to control the blast furnace air intake from the source. After the air volume is controlled at the source, although the reaction in the blast furnace 1 is slightly affected, it can make the top pressure of the blast furnace 1 drop rapidly. The top pressure is reduced, which greatly improves the efficiency of top pressure regulation, so that the current urgent top pressure of the blast furnace can be alleviated; when the top pressure of the blast furnace 1 is too high and the third level alarm is set, the regulation demand of the top pressure of the blast furnace 1 reaches the limit, and the blast furnace is in a relatively dangerous situation. At this time, in addition to the traditional method of directly opening the blast furnace bleed valve 7, the blast furnace blower 32 is also controlled to further reduce the wind for a second time. The blast furnace bleed valve 7 quickly discharges the coal gas from the rear end of the blast furnace, and the blast furnace blower 32 reduces the blast furnace air intake from the front end of the blast furnace. On the basis of the pressure regulating valve 6, the dual combination of the blast furnace bleed valve 7 and the blast furnace blower 32 can be dual-controlled from the front and rear ends of the blast furnace to bleed and relieve the pressure of the blast furnace. Compared with the traditional single-mode bleed of opening the bleed valve from the rear end of the blast furnace, the dual-controlled bleed and pressure relief of the present invention is faster, and the efficiency of relieving high-pressure danger is higher. In other words, it is more secure for high-pressure dangerous situations and has better production safety.

[0051] The safety control method for blast furnace top pressure of the present invention combines the characteristics of various adjustment paths and adjusts the blast furnace top pressure in three stages. When adjusting each stage, not only the problem of blast furnace top pressure reduction but also the problem of blast furnace production are taken into consideration. From the two aspects of blast furnace top pressure reduction and blast furnace production, the blast furnace top pressure is precisely controlled in a targeted manner, so that under the premise of safe and controllable blast furnace top pressure, the production efficiency of the blast furnace is guaranteed to the greatest extent, thereby ensuring the overall production of the blast furnace.

[0052] In addition, the safety control method for blast furnace top pressure of the present invention controls the blast furnace blower 32 to further reduce the air flow twice when the top pressure of the blast furnace 1 is too high. The air volume of the blast furnace blower 32 is reduced to the minimum value that can form a positive pressure in the direction from the hot blast furnace 4 to the blast furnace 1. This setting controls the air volume of the blast furnace blower 32 to the minimum value while preventing the blast furnace 1 from pouring slag into the hot blast furnace 4, allowing the blast furnace 1 to quickly release slag, preventing the blast furnace 1 from exploding under high pressure, and protecting the blast furnace 1 from pouring slag into the hot blast furnace 4, thereby reducing malfunctions of the hot blast furnace 4. In other words, the present invention takes into account both the hot blast furnace 4 and the blast furnace 1, and controls the top pressure of the blast furnace 1 as a whole.

[0053] In the safety control method for blast furnace top pressure of the present invention, the pressure measuring point 8 is located at the top of the blast furnace 1 or in the gas pipeline 51. The pressure measuring point 8 can be a measuring point of a pressure sensor or a measuring point of a flow sensor.

[0054] In the safety control method for the blast furnace top pressure of the present invention, preferably, the number of the pressure measuring points 8 is more than two, and the more than two pressure measuring points 8 are located in different positions. When the top pressure of the blast furnace 1 is judged and graded control is performed under the setting of multiple pressure measuring points 8, it is possible to measure three top pressure N values ​​based on part of the top pressure N, such as three top pressure N values ​​measured by three pressure measuring points 8, and select one or two of the three top pressure N values ​​for comparison and judgment; or take the average value of all top pressures N for comparison and judgment. Compared with a single pressure measuring point 8, multiple pressure measuring points 8 can not only measure the top pressure N, but also judge and analyze whether each pressure measuring point 8 is damaged and whether it is accurate through each measured top pressure N, and once the pressure measuring point 8 is damaged, other pressure measuring points 8 can be replaced online for use.

[0055] In the safety control method for blast furnace top pressure of the present invention, preferably, the number of pressure measuring points 8 is several, and the several pressure measuring points 8 are divided into two or more groups, wherein the first group of pressure measuring points 8 is located at the front end of the gas dust removal and purification device 2, and the second group of pressure measuring points 8 is located at the rear end of the gas dust removal and purification device 2. The first group of pressure measuring points 8, the gas dust removal and purification device 2, the second group of pressure measuring points 8, and the gas turbine 31 are distributed in sequence along the gas path. The first group of pressure measuring points 8 located at the front end of the gas dust removal and purification device 2 can be located at the top of the blast furnace 1 or within the gas pipeline 51 between the blast furnace 1 and the gas dust removal and purification device 2; the second group of pressure measuring points 8 located at the rear end of the gas dust removal and purification device 2 is located within the gas pipeline 51 between the gas dust removal and purification device 2 and the gas turbine 31. When the pressure measuring points 8 are provided at the front and rear ends of the gas dust removal and purification device 2, not only the top pressure N can be measured through the pressure measuring points 8 provided at the front and rear ends, but also the valves of the gas dust removal and purification devices 2 can be judged and analyzed based on the measured top pressures N. For example, if the top pressure N measured by the first group of pressure measuring points 8 is very large and the top pressure N measured by the second group of pressure measuring points 8 is very small, it means that the valves of the gas dust removal and purification device 2 are often closed.

[0056] The safety control method of the blast furnace top pressure of the present invention is preferably that the coal gas dust removal and purification device 2 includes a gravity dust removal device 21 and a dry purification device 22 arranged in sequence along the coal gas path, and the number of the pressure measuring points 8 is several, and the several pressure measuring points 8 are divided into three groups, wherein the first group of pressure measuring points 8 is located at the front end of the gravity dust removal device 21, the second group of pressure measuring points 8 is located at the rear end of the dry purification device 22, and the third group of pressure measuring points 8 is located between the gravity dust removal device 21 and the dry purification device 22. The first group of pressure measuring points 8, the gravity dust removal device 21, the third group of pressure measuring points 8, the dry purification device 22, the second group of pressure measuring points 8 and the gas turbine 31 are distributed in sequence along the coal gas path. The first set of pressure measuring points 8 at the front end of the gravity dust removal device 21 can be located at the top of the blast furnace 1 or within the gas pipeline 51 between the blast furnace 1 and the gravity dust removal device 21. The second set of pressure measuring points 8 at the rear end of the dry purification device 22 is located within the gas pipeline 51 between the gas dust removal and purification device 2 and the gas turbine 31. The third set of pressure measuring points 8 is located within the gas pipeline 51 between the gravity dust removal device 21 and the dry purification device 22. After multiple dust removal and purification processes by the gravity dust removal device 21 and the dry purification device 22, the gas purity is even higher. When the coal gas dust removal and purification device 2 includes the gravity dust removal device 21 and the dry purification device 22, the three groups of pressure measuring points 8 set up can not only measure the top pressure N, but also judge and analyze whether the valves of the gravity dust removal device 21 and the dry purification device 22 are easy to close through each measured top pressure N. If the top pressure N measured by the first group of pressure measuring points 8 is very large, and the top pressure N measured by the second group of pressure measuring points 8 and the top pressure N measured by the third group of pressure measuring points 8 are very small, then it means that the valve of the gravity dust removal device 21 is easy to close; if the top pressure N measured by the first group of pressure measuring points 8 and the top pressure N measured by the third group of pressure measuring points 8 are very large, and the top pressure N measured by the second group of pressure measuring points 8 is very small, then it means that the valve of the dry purification device 22 is easy to close.

[0057] In the safety control method for blast furnace top pressure of the present invention, preferably, the normal pressure parameter M1 is in the range of 204-206 kPa. Preferably, the normal pressure parameter M1 is 205 kPa. During normal blast furnace operation, the top pressure is typically around 205 kPa.

[0058] In the safety control method for blast furnace top pressure of the present invention, preferably, the high pressure parameter M2 is in the range of 209-211 kPa. Preferably, the normal pressure parameter M2 is 210 kPa.

[0059] In the safety control method for blast furnace top pressure of the present invention, preferably, the ultrahigh pressure parameter M3 is in the range of 214-216 kPa. Preferably, the normal pressure parameter M2 is 215 kPa. The maximum withstand pressure of a blast furnace is generally around 215 kPa.

[0060] In the safety control method for blast furnace top pressure of the present invention, preferably, in step S3.3, the blast furnace blower 32 reduces the air pressure by 45-55 kPa at a time. Preferably, the blast furnace blower 32 reduces the air pressure by 50 kPa at a time. During normal blast furnace operation, the top pressure is typically around 205 kPa, and the maximum withstand pressure of a blast furnace is typically around 215 kPa. After the blast furnace blower 32 reduces the air pressure by 45-55 kPa at a time, the top pressure in the blast furnace can be significantly adjusted.

[0061] In the safety control method for blast furnace top pressure of the present invention, preferably, in step S3.4, the blast furnace blower 32 is twice reduced to 25-35 kPa. Preferably, the blast furnace blower 32 is twice reduced to 30 kPa. Under a level 3 alarm, after the blast furnace relief valve 7 is opened, the blast furnace 1 can quickly lose pressure, preventing explosions while also stopping operation. However, after the pressure is lost, the blast furnace 1 is not completely pressure-free, but still has a certain pressure. In this case, the blast furnace blower 32 is twice reduced to 25-35 kPa, rather than completely shutting down, in order to ensure that the hot blast furnace 4 can receive a minimum amount of air. This small amount of air supply, without affecting the pressure relief of the blast furnace 1, allows positive pressure to be generated from the hot blast furnace 4 toward the blast furnace 1, preventing slag from the blast furnace 1 from pouring into the hot blast furnace 4.

[0062] For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A safety control method for blast furnace top pressure, applied to a blast furnace system, characterized by: It includes the following steps: S1. Set a pressure measuring point for monitoring the top pressure in the blast furnace, and monitor the top pressure N in real time through the pressure measuring point; S2. Set normal pressure parameter M1, high pressure parameter M2 and ultra-high pressure parameter M3. M1, M2 and M3 are all non-negative numbers, and M1 < M2 < M3; S3. Based on the top pressure N monitored by the pressure measuring point, judge the top pressure condition of the blast furnace and conduct hierarchical control; specifically: S3.

1. When N < M1, it is judged that the top pressure of the blast furnace is normal and no adjustment is required; S3.

2. When M1 ≤ N < M2, it is judged that the top pressure of the blast furnace is slightly high. At this time, trigger a first-level alarm, and at the same time, control the pressure regulating valve to adjust the top pressure of the blast furnace through the pressure regulating valve; After the adjustment by the pressure regulating valve, if the top pressure N drops to N < M1, stop controlling the pressure regulating valve and return to step S3.1; if the top pressure N continues to rise, then proceed to step S3.3; S3.

3. When M2 ≤ N < M3, it is judged that the top pressure of the blast furnace is medium-high. At this time, trigger a second-level alarm, and at the same time, control the blast furnace blower to make the blast furnace blower reduce the air volume once; After the first air volume reduction of the blast furnace blower, if the top pressure N drops to M1 ≤ N < M2, stop controlling the air volume reduction of the blast furnace blower, and the blast furnace blower resumes normal operation and returns to step S3.2; if the top pressure N continues to rise, then proceed to step S3.4; S3.

4. When N ≥ M3, it is judged that the top pressure of the blast furnace is too high. At this time, trigger a third-level alarm, control the blast furnace blower to make the blast furnace blower reduce the air volume twice, and at the same time, the blast furnace relief valve opens; after the second air volume reduction, the air volume of the blast furnace blower is limited by the condition that the pressure of the hot blast stove is slightly greater than the pressure in the blast furnace and a positive pressure can be formed in the direction from the hot blast stove to the blast furnace.

2. The safety control method for blast furnace top pressure according to claim 1, characterized in that: The pressure measuring point is located at the top of the blast furnace or in the gas pipeline that sequentially connects the gas inlet of the blast furnace, the gas dust removal and purification device and the gas turbine.

3. The safety control method for blast furnace top pressure according to claim 1, characterized in that: The number of the pressure measuring points is more than two, and the more than two pressure measuring points are located at different positions.

4. The method for safety control of blast furnace top pressure according to claim 1, characterized in that: The number of the pressure measuring points is several, and the several pressure measuring points are divided into more than two groups. Among them, the first group of pressure measuring points is located at the front end of the gas dust removal and purification device, the second group of pressure measuring points is located at the rear end of the gas dust removal and purification device, and the first group of pressure measuring points, the gas dust removal and purification device, the second group of pressure measuring points and the gas turbine are sequentially distributed along the gas path.

5. The method for safety control of blast furnace top pressure according to claim 4, characterized in that: The gas dust removal and purification device includes a gravity dust removal device and a dry purification device that are sequentially arranged along the gas path. The number of the pressure measuring points is several, and the several pressure measuring points are divided into three groups. Among them, the first group of pressure measuring points is located at the front end of the gravity dust removal device, the second group of pressure measuring points is located at the rear end of the dry purification device, and the third group of pressure measuring points is located between the gravity dust removal device and the dry purification device. The first group of pressure measuring points, the gravity dust removal device, the third group of pressure measuring points, the dry purification device, the second group of pressure measuring points and the gas turbine are sequentially distributed along the gas path.

6. The method for safety control of blast furnace top pressure according to claim 1, characterized in that: The value range of the normal pressure parameter M1 is 204~206Kpa.

7. The method for safety control of blast furnace top pressure according to claim 1, characterized in that: The value range of the high pressure parameter M2 is 209~211Kpa.

8. The method for safety control of blast furnace top pressure according to claim 1, characterized in that: The value range of the ultra-high pressure parameter M3 is 214~216Kpa.

9. The method for safety control of blast furnace top pressure according to claim 1, characterized in that: In step S3.3, the blast furnace blower reduces the air pressure by 45-55 KPa at a time.

10. The method for safety control of blast furnace top pressure according to claim 1, characterized in that: In step S3.4, the blast furnace blower is reduced to 25-35KPa for the second time.

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