Safety control method for blast furnace top pressure

Abstract

The invention discloses a safety control method for blast furnace top pressure, which is characterized in that the blast furnace top pressure is adjusted in three stages, and the blast furnace top pressures at different stages are respectively adjusted through a pressure adjusting valve, a blast furnace blower, a blast furnace blower and a blast furnace blow-off valve. According to the safety control method for the top pressure of the blast furnace, the top pressure of the blast furnace is adjusted in three stages by combining the characteristics of each adjustment path, during each stage of adjustment, the problem of pressure reduction of the top pressure of the blast furnace is considered, the problem of production of the blast furnace is also considered, and the top pressure of the blast furnace is finely controlled in a targeted manner from the two aspects of pressure reduction of the top pressure of the blast furnace and production of the blast furnace; on the premise that the top pressure of the blast furnace is safe and controllable, the production efficiency of the blast furnace is ensured to the greatest extent, and the overall production of the blast furnace is further ensured.

Description

Technical Field

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

[0002] During the blast furnace smelting process, hot air needs to be fed into the blast furnace to promote the reaction of iron ore in the blast furnace; after the iron ore reacts in the blast furnace, a large amount of CO gas, CO2 gas, H2 and N2 gas (these gases are collectively referred to as blast furnace gas) are generated, which also need to be discharged. In this process of in and out, in order to realize the recycling of blast furnace energy, a blast furnace energy recovery device (Blast Furnace Power Recovery Turbine, referred to as BPRT) is often installed. The BPRT unit designs the gas turbine and blast furnace blower as the same system. Specifically, after the blast furnace gas is output, it is sent to the gas turbine after gravity dust removal and dry purification device, and the gas turbine performs energy conversion. The energy converted and recovered by the gas turbine is then used by the blast furnace blower as the power for the blast furnace hot air supply.

[0003] Maintaining the stability of the blast furnace top pressure (top pressure for short) is one of the important means to ensure the stability of blast furnace production. In order to adjust the blast furnace top pressure when the blast furnace top pressure is too high, under the above blast furnace system, on the one hand, a branch pipe is led out of the blast furnace gas pipeline between the purification device and the gas turbine, and a pressure regulating valve is arranged on the branch pipe. On the other hand, a relief valve is arranged on the top of the blast furnace. When the blast furnace top pressure is too high, when adjusting the blast furnace top pressure, the existing practice is that when the high value is small, it is adjusted by a single pressure regulating valve. At this time, the blast furnace is not completely depressurized and can continue to work; when the high value is large, the regulating valve is fully opened, or the relief valve is directly opened. After the regulating valve is fully opened or the relief valve is opened, the blast furnace loses pressure and stops working.

[0004] Under the above adjustment method, the adjustment path is extremely limited. On the one hand, before the regulating 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, and the blast furnace can continue to work without complete pressure loss. Its dependence on the pressure regulating valve is too high, which 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 the front end of the pressure regulating valve fails, such as the shut-off valve at the inlet of the gravity dust collector 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 regulating 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来不及开启, resulting in 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 regulating valve, only the regulating 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 object 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 object 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: 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. According to the top pressure N monitored by the pressure measuring point, judge the top pressure situation of the blast furnace and perform 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 through 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 perform 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 reduction of the blast furnace blower, if the top pressure N drops to M1 ≤ N < M2, stop the reduction control 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 determined that the top pressure of the blast furnace is too high. At this time, a third-level alarm is triggered, and the blast furnace blower is controlled to perform a second reduction of the blast furnace blower. At the same time, the blast furnace relief valve is opened; after the second reduction of the blast furnace blower, 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.

[0007] Further, the pressure measurement 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 measurement point can be the measurement point of a pressure sensor or the measurement point of a flow sensor.

[0008] Further, the number of the pressure measurement points is two or more, and the two or more pressure measurement points are located at different positions. With the setting of multiple pressure measurement points, when judging the top pressure situation of the blast furnace and performing hierarchical control, it is possible to rely on a partial top pressure N. For example, if three pressure measurement 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 top pressure N values can be taken for comparison and judgment. Compared with a single pressure measurement point, multiple pressure measurement points can not only measure the top pressure N, but also judge and analyze whether each pressure measurement point is damaged and accurate through the measured top pressure N. And once a pressure measurement point is damaged, other pressure measurement points can also be replaced online for use.

[0009] Furthermore, the number of the pressure measuring points is several, and the several pressure measuring points are divided into two or more groups, wherein the first group of pressure measuring points is located at the front end of the coal gas dust removal and purification device, and the second group of pressure measuring points is located at the rear end of the coal gas dust removal and purification device, and the first group of pressure measuring points, the coal gas dust removal and 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 coal gas dust removal and purification device can be located at the top of the blast furnace, or in the coal gas pipeline between the blast furnace and the coal gas dust removal and purification device; the second group of pressure measuring points located at the rear end of the coal gas dust removal and purification device is located in the coal gas pipeline between the coal gas dust removal and purification device and the coal gas turbine. When the pressure measuring points are arranged 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 arranged at the front and rear ends, but also the measured top pressures N can be used to judge and analyze whether the valves of the gas dust removal and purification device are normally closed. 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, then it means that the valves of the gas dust removal and purification device are normally closed.

[0010] Further, 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, and 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; 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, 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.

[0011] Furthermore, the value range of the normal pressure parameter M1 is 204-206 KPa. Preferably, the normal pressure parameter M1 is 205 KPa. During normal production of the blast furnace, the top pressure is usually around 205 KPa.

[0012] Further, the value range of the high pressure parameter M2 is 209-211 KPa. Preferably, the normal pressure parameter M2 is 210 KPa.

[0013] Furthermore, the value range of the ultra-high pressure parameter M3 is 214-216 KPa. Preferably, the normal pressure parameter M2 is 215 KPa. The maximum withstand pressure of a blast furnace is usually around 215 KPa.

[0014] Furthermore, in step S3.3, the blast furnace blower reduces the air pressure by 45-55Kpa at a time. Preferably, the blast furnace blower reduces the air pressure by 50Kpa at a time. During normal production of a blast furnace, the top pressure is usually around 205Kpa, and the maximum withstand pressure of a blast furnace is usually around 215Kpa. After the blast furnace blower reduces the air pressure by 45-55Kpa at a time, the top pressure in the blast furnace can be greatly adjusted.

[0015] Furthermore, in step S3.4, the blast furnace blower reduces the air pressure to 25~35Kpa for the second time. Preferably, the blast furnace blower reduces the air pressure to 30Kpa for the second time. Under the third-level alarm, after the blast furnace relief valve is opened, the blast furnace can lose pressure quickly to prevent explosion and stop working. However, the blast furnace after the pressure loss is not completely pressure-free, but still has a certain pressure. In this case, the blast furnace blower reduces the air pressure to 25~35Kpa for the second time, and the setting of not completely stopping the machine is to ensure that the hot blast furnace can have a minimum air supply. The small air supply 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.

[0016] The safety control method for blast furnace top pressure of the present invention, in addition to the regulating paths of the pressure regulating valve and the blast furnace relief valve, adds a regulating path for reducing the airflow of the blast furnace blower. Compared with the traditional top pressure control method with only a pressure regulating valve and a relief valve, on the one hand, the present application includes more regulating paths for the pressure regulating valve, the blast furnace relief valve and the blast furnace blower. With more regulating paths, the regulating paths have more selectivity, are more flexible, and are more conducive to refined control; on the other hand, after adding the regulating path for reducing the airflow of the blast furnace blower, since the blast furnace blower is not only located at the air inlet end of the blast furnace, 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 top pressure of the blast furnace can be fundamentally changed, and the regulation and control of the blast furnace top pressure is more effective and efficient.

[0017] The safety control method of the blast furnace top pressure of the present invention, after developing three ways to adjust the blast furnace top pressure, adjusts the blast furnace top pressure in three stages. Compared with the simple and crude two-level adjustment of the traditional pressure regulating valve and the relief valve, the adjustment accuracy is higher, and the change control of each top pressure can be more accurate. For example, when the blast furnace is originally high, the relief valve is directly opened to relieve the pressure and prevent the blast furnace from explosion; and in the safety control method of the blast furnace top pressure of the present invention, when the blast furnace is high, the blast furnace blower is first used to reduce the wind to adjust it. After the blast furnace blower is adjusted, the blast furnace top pressure drops. When it no longer rises, the relief valve will not be directly opened. It is precisely because it can be controlled more accurately that the blast furnace production efficiency of the present invention can be higher, and the frequency of shutdown due to pressure loss when the relief valve is opened is lower.

[0018] 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, while 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 the first-level alarm is triggered, the regulating demand for the top pressure of the blast furnace is small and the urgency of regulation is low. At this time, the 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 first-level 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 the second-level alarm is triggered, 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 top pressure of the blast furnace can be rapidly reduced. The efficiency of top pressure regulation is greatly improved, so that the current urgent top pressure of the blast furnace can be alleviated; when the top pressure of the blast furnace is too high and the third-level alarm is triggered, the regulation demand of the top pressure of the blast furnace 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 wind 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 blast furnace vent valve and the blast furnace blower are dually combined, which can be dually 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 from the rear end of the blast furnace by opening the vent valve, the dual-controlled venting and pressure relief speed of the present invention is faster, and the efficiency of relieving high-pressure danger is higher. In other words, it is more secure and has better production safety in the case of high-pressure danger.

[0019] The safety control method of the blast furnace top pressure of the present invention combines the characteristics of each adjustment path to adjust 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 finely 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.

[0020] 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 controlled to further 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 release pressure, preventing the blast furnace from exploding under high pressure, and protecting the blast furnace from pouring slag into the hot blast stove, reducing the failures 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. Description of the Drawings

[0021] 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; Figure 2 is a flow chart of the safety control method for the top pressure of the blast furnace of the present invention. Detailed Embodiments

[0022] The following describes in detail the preferred embodiments of the safety control method for the top pressure of the blast furnace of the present invention with reference to the drawings: As Figure 1 and Figure 2 shown, a safety control method for the top pressure of a blast furnace includes the following steps: 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; 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 8, judge the top pressure situation of the blast furnace 1 and perform hierarchical control; specifically: S3.1. When N < M1, judge that the top pressure of the blast furnace 1 is normal and no adjustment is required; 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; 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; S3.3. When M2 ≤ N < M3, judge that the top pressure of the blast furnace 1 is medium-high. At this time, trigger a second-level alarm, and at the same time, control the blast furnace blower 32 to make the blast furnace blower 32 reduce the air volume for the first time; After the primary air volume reduction of the blast furnace blower 32, if the top pressure N drops to M1 ≤ N < M2, stop the air volume reduction control of the blast furnace blower 32, and the blast furnace blower 32 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 determined that the top pressure of the blast furnace 1 is too high. At this time, a third-level alarm is triggered, and the blast furnace blower 32 is controlled to perform secondary air volume reduction. At the same time, the blast furnace relief valve 7 is opened; after the secondary air volume 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.

[0023] 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 is provided with 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.

[0024] In the blast furnace system to which the safety control method for the top pressure of the blast furnace in the present invention is applied, the hot blast stove 4 burns to provide hot blast for the blast furnace 1; the blast furnace blower 32 is used to provide power for transporting hot blast from the hot blast stove 4 into the blast furnace 1; iron ore reacts inside the blast furnace 1 to form gas; the gas dust removal and purification device 2 is used to remove dust and purify the gas output from the blast furnace 1. The BPRT unit 3 connects the gas turbine 31 and the blast furnace blower 32 into a system, mainly for the recovery and utilization of the energy in the gas; wherein, the gas turbine 31 is used to convert the energy in the gas for recovery; after the gas turbine 31 recovers the energy in the gas, it is provided to the blast furnace blower 32 for reuse by the blast furnace blower 32. The pressure regulating valve 6 is installed on the branch pipe 52. By adjusting the opening and closing of the pressure regulating valve 6 in proportion, the output volume 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 installed at the top of the blast furnace 1. After the blast furnace relief valve 7 is opened, the gas inside the blast furnace 1 can be directly discharged from the blast furnace relief valve 7.

[0025] When the blast furnace system is working, the hot blast stove 4 burns. Under the power action of the blast furnace blower 32, hot blast is continuously provided to the blast furnace 1 to promote the reaction of iron ore in the blast furnace 1. The iron ore in the blast furnace 1 reacts to form a large amount of gas. This gas enters the gas pipeline 51 from the top of the blast furnace 1, and then enters the gas dust removal and purification device 2 along the gas pipeline 51, and is dust-removed and purified by the gas dust removal and purification device 2; the gas dust-removed and purified by the gas dust removal and purification device 2 is sent to the gas turbine 31 along the gas pipeline 51, and the energy in the gas is converted and recovered by the gas turbine 31; the recovered energy is provided to the blast furnace blower 32 for reuse by the blast furnace blower 32.

[0026] In the safety control method of the blast furnace top pressure of the present invention, the top pressure N of the blast furnace 1 is monitored in real time through the pressure measuring point 8, and based on the monitored top pressure N, the top pressure situation of the blast furnace 1 is judged in real time and classified control is carried out. Before the judgment, according to the daily working data of the blast furnace top pressure, the normal pressure parameter M1, the high pressure parameter M2 and the ultra-high pressure parameter M3 are set correspondingly. 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 blast furnace top pressure 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 the adjustment of the blast furnace top pressure by the pressure regulating valve 6 after the first-level alarm, the blast furnace blower 32 is also controlled to reduce the air volume once; 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 the adjustment of the blast furnace top pressure by the pressure regulating valve 6 after the first-level alarm and the control of the blast furnace blower 32 to reduce the air volume once after the second-level alarm, the blast furnace blower 32 is further controlled to reduce the air volume twice. After the second air volume reduction, the air volume of the blast furnace blower 32 is limited by the pressure of the hot blast stove 4 being slightly greater than the pressure in 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.

[0027] In the safety control method of the blast furnace top pressure of the present invention, there are three adjustment ways for the blast furnace top pressure: 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 blast furnace air outlet end, and the blast furnace top pressure is adjusted and controlled by controlling the gas discharge flow rate at the blast furnace air outlet end; the blast furnace blower 32 is the power for the blast furnace to intake air and is the source of the blast furnace top pressure. It is located at the blast furnace air inlet end, and the blast furnace top pressure is adjusted and controlled by controlling the air intake of the blast furnace.

[0028] In addition to the regulating paths of the pressure regulating valve 6 and the blast furnace relief valve 7, the safety control method for the blast furnace top pressure of the present invention adds a regulating path for reducing the airflow of the blast furnace blower 32. Compared with the traditional top pressure control method with only a pressure regulating valve and a relief valve, on the one hand, the present application includes more regulating paths for the pressure regulating valve 6, the blast furnace relief valve 7 and the blast furnace blower 32. With more regulating paths, the selectivity of the regulating paths is more, more flexible, and more conducive to refined control; on the other hand, after adding the regulating path for reducing the airflow of the blast furnace blower 32, since the blast furnace blower 32 is not only located at the air inlet end of the blast furnace, but also the source of the top pressure of the blast furnace 1, when the source of the blast furnace top pressure is controlled by the blast furnace blower 32, the top pressure of the blast furnace can be fundamentally changed, and the regulation and control of the blast furnace top pressure is more effective and efficient.

[0029] The safety control method for blast furnace top pressure of the present invention, after developing three ways to adjust the blast furnace top pressure, adjusts the blast furnace top pressure in three stages. Compared with the simple and crude two-stage adjustment of the traditional pressure regulating valve and the relief valve, the adjustment accuracy is higher, and the change control of each top pressure can be more accurate. For example, when the blast furnace is originally high, the relief valve is directly opened to relieve the pressure and prevent the blast furnace from explosion; and in the safety control method for blast furnace top pressure of the present invention, when the blast furnace is high, the blast furnace blower 32 is first used to reduce the wind to adjust it. After the blast furnace blower 32 is adjusted, the blast furnace top pressure drops. When it no longer rises, the relief valve will not be directly opened. It is precisely because it can be controlled more accurately that the blast furnace production efficiency of the present invention can be higher, and the frequency of shutdown due to pressure loss when the relief valve is opened is lower.

[0030] 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, the adjustment of 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 the first-level alarm is triggered, the adjustment demand for the top pressure of the blast furnace 1 is small and the urgency of adjustment 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 the second-level alarm is triggered, 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 of the blast furnace 1 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 vent valve 7, the blast furnace blower 32 is also controlled to further reduce the wind for a second time. The blast furnace vent 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 vent valve 7 and the blast furnace blower 32 can be dually 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 venting from the rear end of the blast furnace by opening the vent valve in a single way, the dual-controlled venting and pressure relief speed of the present invention is faster, and the efficiency of relieving high-pressure danger is higher. In other words, it is more secure and has better production safety for the situation of high-pressure danger.

[0031] The safety control method of the blast furnace top pressure of the present invention combines the characteristics of each adjustment path to adjust 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 finely 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.

[0032] In addition, the safety control method of the blast furnace top pressure of the present invention, when the top pressure of the blast furnace 1 is too high and the blast furnace blower 32 is controlled to further reduce the air for a second time, the air volume of the blast furnace blower 32 is reduced to the minimum value that can form a positive pressure 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 under the premise of preventing the blast furnace 1 from pouring slag into the hot blast furnace 4, so that the blast furnace 1 is quickly released, and the high-pressure explosion of the blast furnace 1 is prevented. At the same time, it can also protect the blast furnace 1 from pouring slag into the hot blast furnace 4, reducing the failure 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.

[0033] In the safety control method of 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.

[0034] In the safety control method of 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 at different positions. Under the setting of multiple pressure measuring points 8, when judging the top pressure of the blast furnace 1 and performing graded control, 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 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.

[0035] In the safety control method of the blast furnace top pressure of the present invention, preferably, the number of the 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 coal gas dust removal and purification device 2, and the second group of pressure measuring points 8 is located at the rear end of the coal gas dust removal and purification device 2, and the first group of pressure measuring points 8, the coal gas dust removal and purification device 2, the second group of pressure measuring points 8 and the coal gas turbine 31 are distributed in sequence along the coal gas path. The first group of pressure measuring points 8 located at the front end of the coal gas dust removal and purification device 2 can be located at the top of the blast furnace 1, or can be located in the coal gas pipeline 51 between the blast furnace 1 and the coal gas dust removal and purification device 2; the second group of pressure measuring points 8 located at the rear end of the coal gas dust removal and purification device 2 is located in the coal gas pipeline 51 between the coal gas dust removal and purification device 2 and the coal 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 top pressure N can be used to judge and analyze whether the valves of the gas dust removal and purification device 2 are normally closed. 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, then it means that the valves of the gas dust removal and purification device 2 are normally closed.

[0036] The safety control method of 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, 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, and 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 group of pressure measuring points 8 located at the front end of the gravity dust removal device 21 can be located at the top of the blast furnace 1, or in the gas pipeline 51 between the blast furnace 1 and the gravity dust removal device 21; the second group of pressure measuring points 8 located at the rear end of the dry purification device 22 is located in the gas pipeline 51 between the gas dust removal and purification device 2 and the gas turbine 31; the third group of pressure measuring points 8 is located in the gas pipeline 51 between the gravity dust removal device 21 and the dry purification device 22. After multiple dust removal and purification by the gravity dust removal device 21 and the dry purification device 22, the purity of the gas is 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 often closed 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 often closed; 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 often closed.

[0037] In the safety control method for blast furnace top pressure of the present invention, preferably, the value range of the normal pressure parameter M1 is 204-206Kpa. Preferably, the normal pressure parameter M1 is 205Kpa. During normal production of the blast furnace, the top pressure is usually around 205Kpa.

[0038] In the safety control method for blast furnace top pressure of the present invention, preferably, the value range of high pressure parameter M2 is 209-211 KPa. Preferably, the normal pressure parameter M2 is 210 KPa.

[0039] In the safety control method for blast furnace top pressure of the present invention, preferably, the value range of the ultra-high pressure parameter M3 is 214-216 KPa. Preferably, the normal pressure parameter M2 is 215 KPa. The maximum withstand pressure of a blast furnace is usually about 215 KPa.

[0040] 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 45-55Kpa at a time. Preferably, the blast furnace blower 32 reduces the air pressure by 50Kpa at a time. During normal production of the blast furnace, the top pressure is usually about 205Kpa, and the maximum withstand pressure of the blast furnace is usually about 215Kpa. After the blast furnace blower 32 reduces the air pressure by 45-55Kpa at a time, the top pressure in the blast furnace can be greatly adjusted.

[0041] The safety control method of blast furnace top pressure of the present invention is preferably that in step S3.4, the blast furnace blower 32 reduces the air pressure to 25~35Kpa for the second time. Preferably, the blast furnace blower 32 reduces the air pressure to 30Kpa for the second time. Under the third-level alarm, after the blast furnace relief valve 7 is opened, the blast furnace 1 can lose pressure quickly to prevent explosion and stop working. However, the blast furnace 1 after the pressure loss is not completely pressure-free, but still has a certain pressure. In this case, the blast furnace blower 32 reduces the air pressure to 25~35Kpa for the second time, and the setting of not completely stopping the machine is to ensure that the hot blast furnace 4 can have a minimum air supply. The small air supply can form a positive pressure from the hot blast furnace 4 to the direction of the blast furnace 1 without affecting the pressure relief of the blast furnace 1, so as to prevent the blast furnace 1 from pouring slag into the hot blast furnace 4.

[0042] 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 protection scope of the present invention.

Claims

1. A safety control method for blast furnace top pressure, applied to a blast furnace system, characterized in that: It includes the following steps: S1. Set pressure measuring points for monitoring the top pressure in the blast furnace, and monitor the top pressure N in real time through the pressure measuring points; 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 points, judge the top pressure situation of the blast furnace and perform 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 perform step S3.3; S3.

3. When M2 ≤ N < M3, it is judged that the top pressure of the blast furnace is moderately 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, the blast furnace blower resumes normal operation, and return to step S3.2; if the top pressure N continues to rise, then perform 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, open the blast furnace relief valve; 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 method for safety control of blast furnace top pressure according to claim 1, characterized in that: The pressure measuring points are 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.

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 - 206 Kpa.

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 209-211 KPa. Preferably, the normal pressure parameter M2 is 210 KPa.

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 reduces the air pressure to 25-35Kpa for a second time.

Images