Leakage detection method for rotational flow degassing of blast furnace soft water cooling system

Abstract

The invention relates to the technical field of blast furnace ironmaking, in particular to a leak detection method for rotational flow degassing of a blast furnace soft water cooling system, which comprises the following steps of: 1, testing the concentration of CO gas exhausted by a vertical rotational flow degassing tank in the blast furnace soft water cooling system; 2, when the concentration of CO gas exhausted by the vertical cyclone degassing tank is larger than 11%, a water return valve is closed firstly, then a water inlet valve is closed, and then the pressure in a pipeline between the water return valve and the water inlet valve is monitored; 3, the pipelines with internal leakage or external leakage are changed to be communicated with industrial water, the other pipelines are changed to be spanning pipes, the pipelines with internal leakage or external leakage are spanned, and soft water cooling is recovered; and 4, testing the concentration of the CO gas discharged by the vertical cyclone degassing tank in the blast furnace soft water cooling system again. Cooling water and blast furnace gas in a blast furnace soft water cooling system are separated by using the vertical cyclone degassing tank, so that the separation efficiency of the blast furnace gas is improved; the pipeline with internal leakage or external leakage is changed to be communicated with industrial water, so that the cooling efficiency of other branch pipes without water leakage in the cooling wall is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of blast furnace ironmaking, and particularly relates to a leak detection method for swirl degassing of a soft water cooling system in a blast furnace. Background Art

[0002] The blast furnace cooling system is an important part of blast furnace equipment. Its main functions are to protect the blast furnace lining, maintain a reasonable operating furnace profile, ensure the normal production of the blast furnace, and extend the service life of the blast furnace. The blast furnace cooling system mainly consists of a cooling medium, cooling equipment, circulating pipelines, water pumps, heat exchangers, monitoring and control devices, etc. The cooling equipment is the core component that directly performs the cooling task in the blast furnace cooling system. The cooling equipment is distributed in different parts of the blast furnace, such as the furnace body, hearth, bottom, and tuyeres, and can precisely cool according to the heat load conditions of each part of the blast furnace. While protecting the furnace lining and shell, it ensures the stable operation of the blast furnace. Common cooling equipment includes cooling stave, cooling water tank, tuyere cooling device, and bottom cooling device. Among them, the cooling stave is the cooling equipment that directly contacts the blast furnace lining and shell. It can cool the inside of the blast furnace over a large area, efficiently transfer the heat in the blast furnace by using the internally circulated cooling medium, and keep the furnace lining and shell within a safe working temperature range, playing an irreplaceable role in maintaining the overall heat balance of the blast furnace.

[0003] The service life of the cooling stave directly affects the life of one generation of the furnace. Due to the harsh working environment of the cooling stave, which endures high-temperature thermal stress, charge erosion, and alkali metal corrosion for a long time, the service life of the cooling stave is severely threatened. The prior art usually connects the cooling stave to a soft water closed-circuit cooling system in the blast furnace and uses softened soft water as the cooling medium. Soft water has good heat conduction performance and a low scaling tendency, can efficiently take away the heat absorbed by the cooling stave, and avoid forming scale in the internal pipelines of the cooling stave, thereby playing a role in protecting the blast furnace cooling stave and extending its service life. The cooling stave runs through multiple hot zones of the blast furnace, such as the bottom, hearth, waist, body, and throat, has multiple segments, and the internal pipeline shapes are diverse and complex. In addition, the cooling stave is usually installed between the furnace shell and refractory material and has the characteristic of being invisible. When the cooling stave leaks, it is very difficult to find the leak point in a short time, which will not only lead to a reduction in the cooling efficiency of the remaining non-leaking branch pipes and a decrease in the calorific value of blast furnace gas, but also shorten the service life of the cooling stave. Summary of the Invention

[0004] In view of the technical problems that it is difficult to find the leakage points of the cooling stave in the soft water closed-circuit cooling system of blast furnaces in a short time, which will lead to a decrease in the cooling efficiency of the remaining branch pipes and a decrease in the calorific value of blast furnace gas, the present invention provides a leak detection method for swirl degassing in the soft water cooling system of blast furnaces. The vertical swirl degassing tank is used to separate the cooling water and blast furnace gas in the soft water cooling system of blast furnaces, improving the separation efficiency of blast furnace gas; by redirecting the pipes with internal or external leakage to industrial water, the cooling efficiency of the remaining non-leaking branch pipes inside the cooling stave is ensured.

[0005] The technical solution of the present invention is as follows: A leak detection method for pressure testing and swirl degassing in the soft water cooling system of blast furnaces, comprising the following steps: Step 1: Test the CO gas concentration discharged from the outside of the vertical swirl degassing tank in the soft water cooling system of blast furnaces. Step 2: When the CO gas concentration discharged from the outside of the vertical swirl degassing tank is greater than 11%, first close the return water valve, then close the inlet water valve, and then monitor the pressure inside the pipe between the return water valve and the inlet water valve. If the pressure inside the pipe between the return water valve and the inlet water valve ≥ 1.1 MPa, the pipe between the return water valve and the inlet water valve is not damaged; if the pressure inside the pipe between the return water valve and the inlet water valve is less than 1.1 MPa, there is internal or external leakage in the pipe between the return water valve and the inlet water valve. Step 3: Redirect the pipes with internal or external leakage to industrial water, and redirect the remaining pipes to cross pipes, crossing the pipes with internal or external leakage, and resume soft water cooling. Step 4: Test the CO gas concentration discharged from the outside of the vertical swirl degassing tank in the soft water cooling system of blast furnaces again. When the CO gas concentration discharged from the outside of the vertical swirl degassing tank ≤ 11%, it is determined that the pipe leak points in the soft water cooling system of blast furnaces have been eliminated; when the CO gas concentration discharged from the outside of the vertical swirl degassing tank is greater than 11%, repeat Steps 2 to 4.

[0006] Further, in Step 1, the soft water cooling system of blast furnaces is a soft water closed-circuit cooling system of blast furnaces. The soft water closed-circuit cooling system of blast furnaces includes a plurality of parallel soft water cooling pipelines, and the soft water cooling pipelines are circumferentially distributed inside the furnace shell of the blast furnace. Preferably, the soft water cooling pipelines are evenly distributed circumferentially along the inside of the furnace shell. The present invention adopts the piping principle of "step by step up", without setting any downward detouring pipelines, which is beneficial to eliminating air resistance, stabilizing the flow rate of cooling water, and ensuring cooling uniformity.

[0007] Further, the soft water cooling pipeline includes a plurality of series-connected cooling staves; the soft water cooling pipeline stands vertically inside the furnace shell of the blast furnace along the vertical direction. The lower end of the soft water cooling pipeline is the inlet, and the pressure at the inlet of the soft water cooling pipeline is 1.1 MPa. The upper end of the soft water cooling pipeline is the outlet, and the pressure at the outlet of the soft water cooling pipeline is 0.3 MPa. Each cooling stave of the soft water cooling pipeline adopts the cooling method of "one string to the top".

[0008] Further, in step one, the vertical cyclone degassing tank is located at the top of the blast furnace. The vertical cyclone degassing tank is connected to the outlet of the soft water cooling pipeline. In the present invention, the vertical cyclone degassing tank is used to separate the cooling water and the blast furnace gas. After the cooling water enters the tank body, its linear motion changes to circular motion. The bubbles mixed in the water also rotate and flow upward along the inner wall of the tank body. The rotational flow can increase the flow length of the cooling water and more fully achieve the separation of water and gas. Under the buoyancy of the water and the upward inertia, the bubbles will accelerate and escape from the liquid surface, thus achieving the purpose of rapid and efficient degassing. Using the vertical cyclone degassing tank for leak detection of the cooling equipment can quickly remove the blast furnace gas carried by the cooling water and quickly and accurately determine whether the cooling system leaks.

[0009] Further, the vertical cyclone degassing tank includes a tank body. An inlet is provided at the lower part of the tank body, and an inlet valve is arranged at the inlet. The inlet accesses the tank body from bottom to top, and the included angle between the inlet and the tank body is 20°, so that the water flow generates a swirling motion upward after entering the interior of the tank body along the inlet; an outlet is also provided at the lower part of the tank body, and an outlet valve is arranged at the outlet. The outlet is connected to the inlet of the expansion tank, the outlet of the expansion tank is connected to the inlet of the centrifugal pump, and the outlet of the centrifugal pump is connected to the inlet of the soft water cooling pipeline. An automatic exhaust valve and a manual exhaust valve are arranged at the top of the vertical cyclone degassing tank. The automatic exhaust valve and the manual exhaust valve can be switched according to needs. The automatic exhaust valve and the manual exhaust valve are respectively connected to the gas alarm. Through the gas alarm, it is possible to detect the leakage of the cooling wall in the first time. A drain valve is arranged at the bottom of the vertical cyclone degassing tank. The inlet of the vertical cyclone degassing tank is connected to the outlet of the soft water cooling pipeline through the inlet valve. The inner wall of the vertical cyclone degassing tank is sprayed with polyurethane to increase the smoothness of the inner wall surface, which is beneficial to promoting the spiral upward movement of the soft water from bottom to top.

[0010] Further, the water flow enters the interior of the tank body along the inlet at a flow rate of 7 - 10 m / s.

[0011] Further, in step two, the pipeline between the return water valve and the inlet valve is a branch pipe inside the cooling wall. A plurality of bypass valves are arranged on the branch pipe inside the cooling wall, and the bypass valves are used to connect the pressure gauges. The return water valve and the inlet valve are respectively installed with a return water quick connector and an inlet quick connector. The return water valve and the inlet valve can be respectively arranged at the upper end and the lower end of the branch pipe inside the cooling wall, or can be respectively arranged at the upper end and the lower end of each section of the cooling wall to facilitate sectional pressure testing to check the leakage point of the cooling water.

[0012] Further, in Step 2, if the pressure in the pipeline between the return water valve and the inlet water valve is 0.45 - 1.1 Mpa, there is an internal leak in the pipeline between the return water valve and the inlet water valve. An internal leak means that the cooling medium inside the cooling stave leaks from the pipeline or weld to the furnace chamber or the space inside the furnace, rather than directly flowing out of the equipment to the outside; if the pressure in the pipeline between the return water valve and the inlet water valve is less than 0.45 MPa, there is an external leak in the pipeline between the return water valve and the inlet water valve. An external leak means that the cooling medium leaks from the pipeline or connection part of the cooling stave to the external environment of the equipment. For example, cooling water seeps out or splashes onto the surrounding area from the outer wall of the furnace shell.

[0013] Further, when there is an internal leak in the pipeline between the return water valve and the inlet water valve, analyze the H2 content in the blast furnace gas discharged from the normal gas outlet channel at the top of the blast furnace online, and adjust the fuel ratio according to the following formula: Fuel ratio = [J + (η1 - η0) × 100 × 0.1] + [M + (η1 - η0) × 100 × 0.15 + (∆T - ∆T1) × 0.8], where, J: reference coke ratio, J takes the coke ratio of the nearest 3 smelting cycles to the current time, unit: kg / t; M: reference coal ratio, M takes the coal ratio of the nearest 1.5 smelting cycles to the current time, unit: kg / t; η1: current value of hydrogen content, the H2 content in the blast furnace gas currently discharged from the normal gas outlet channel at the top of the blast furnace, unit: %; η0: reference value of hydrogen content, takes the real-time average value of the nearest 1 smelting cycle to the current time, unit: %; ∆T: current value of the temperature difference between the inlet and outlet water of the cooling stave, unit: °C; ∆T1: reference value of the temperature difference between the inlet and outlet water of the cooling stave, ∆T1 takes the real-time average value of the nearest 1 smelting cycle to the current time, unit: °C; Among them, the smelting cycle is judged in real time according to the current charging speed and smelting intensity.

[0014] According to the calculation result, adjust the fuel ratio. By adjusting the fuel ratio, effectively avoid the reduction of furnace temperature caused by internal leakage of cooling water and maintain the normal operation state inside the furnace.

[0015] Furthermore, in step three, a metal hose is used to pass industrial water into the pipe with internal or external leakage. Quick connectors are provided on both sides of the metal hose, and the quick connectors are preferably buckle-type quick connectors. When changing the industrial water supply, one metal hose can be used to connect the inlet valve of the pipe with internal or external leakage to the industrial water source, while another metal hose is used to connect the return valve of the pipe with internal or external leakage to the industrial water reservoir. The buckle-type quick connectors of the two metal hoses are used in conjunction with the return water quick connector and the inlet water quick connector, respectively, to achieve rapid replacement of the metal hoses and the pipe with internal or external leakage, shortening the water change time to 1-2 minutes. The buckle-type quick connector is preferably a Type A quick connector (without pull ears) or a Type B quick connector (with pull ears). The Type A quick connector is used in conjunction with the Type B quick connector. The Type A quick connector is inserted as a male connector into the groove of the Type B quick connector as a female connector and then rotated to lock. A sealing ring (such as silicone or rubber) is used to increase the airtightness of the connection.

[0016] The beneficial effects of the present invention are: The present invention provides a leak detection method for cyclone degassing in a blast furnace soft water cooling system. The method first determines whether a cooling water leak exists in the blast furnace cooling stave based on the CO gas concentration discharged from a vertical cyclone degassing tank in the blast furnace soft water cooling system. When a leak exists in the blast furnace cooling stave, the return valve and the inlet valve are regulated to pressurize the pipeline with cooling water. The pressure in the pipeline between the return valve and the inlet valve is then monitored to identify the leak. The pipeline experiencing internal or external leakage is then routed to industrial water, and the remaining pipelines are replaced with span pipes that span the leaking pipeline. Soft water cooling is then restored. This method prevents the pressure in the remaining pipelines not experiencing internal or external leakage from being affected, while also allowing the leaking pipeline to continue to function, thereby maintaining a stable cooling effect in the cooling stave.

[0017] The present invention uses a vertical cyclone degassing tank to separate cooling water and blast furnace gas, which is beneficial to improving the degassing effect and increasing the operating stability of the cooling system. The reduction of bubbles in the water can increase the subheat of the water, improve the cooling efficiency, and avoid the occurrence of gas blockage that causes the cooling system to be unable to circulate.

[0018] The present invention adopts the method of pressing the cooling wall in sections or pressing one by one to determine the damaged branch pipe of the cooling wall, thereby realizing the precise control of the cooling water leakage point of the cooling wall. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0020] Figure 1It is a physical diagram of the return water valve after installing the return water quick connector in Embodiment 1 of the present invention.

[0021] Figure 2 It is a schematic structural diagram of the vertical cyclone degassing tank in Embodiment 1 of the present invention.

[0022] Figure 3 It is a schematic diagram of the cooling water flow direction and flow rate of the blast furnace soft water closed-loop cooling system in Embodiment 3 of the present invention.

[0023] In the figure, 1-1: manual exhaust valve, 1-2: automatic exhaust valve, 2: liquid level line, 3: tank body, 4: inlet valve, 5: outlet valve, 6: blowdown valve, 7: bracket. Detailed implementation manners

[0024] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0025] Embodiment 1 A leak detection method for pressure testing and cyclone degassing of a blast furnace soft water cooling system includes the following steps: Step 1: Test the concentration of CO gas discharged from the outside of the vertical cyclone degassing tank in the blast furnace soft water closed-loop cooling system. The blast furnace soft water closed-loop cooling system includes a plurality of parallel soft water cooling pipelines, which are evenly distributed circumferentially along the inner side of the furnace shell. The soft water cooling pipelines are vertically arranged along the inner side of the furnace shell of the blast furnace. The lower end of the soft water cooling pipeline is the inlet, and the pressure at the inlet of the soft water cooling pipeline is 1.1 MPa. The upper end of the soft water cooling pipeline is the outlet, and the pressure at the outlet of the soft water cooling pipeline is 0.3 MPa. The soft water cooling pipeline includes a plurality of series-connected cooling walls, and each cooling wall of the soft water cooling pipeline adopts a "one-string-to-the-top" cooling method. The series-connected cooling walls on the same soft water cooling pipeline penetrate the furnace bottom, furnace belly, furnace waist, furnace body and furnace throat of the blast furnace from bottom to top. In this embodiment, the "step-by-step" pipe laying principle is adopted, and no downward detoured pipelines are set.

[0026] The outlet of the soft water cooling pipeline is connected to the inlet of the vertical cyclone degassing tank through an inlet valve. The vertical cyclone degassing tank is located at the top of the blast furnace, and the volume of the vertical cyclone degassing tank is 35m 3 . As Figure 2As shown in the figure, the vertical cyclone degassing tank includes a tank body 3. Inside the tank body 3, there is a liquid level line 2. The lower part of the tank body 3 is provided with a water inlet, and a water inlet valve 4 is arranged at the water inlet. The water inlet accesses the tank body 3 from bottom to top, and the included angle between the water inlet and the tank body 3 is 20°, so that the cooling water flows into the inside of the tank body 3 along the water inlet at a flow rate of 7 - 10 m / s. After the cooling water enters the inside of the tank body 3 along the water inlet, it undergoes a swirling motion from bottom to top; the lower part of the tank body 3 is also provided with a water outlet. The water outlet of the tank body 3 is arranged on the opposite side of the water inlet of the tank body 3. A water outlet valve 5 is arranged at the water outlet, and the water outlet is connected to the water inlet of the expansion tank through the water outlet valve 5. A drain valve 6 is arranged at the central position of the bottom of the tank body 3. A support 7 is also arranged at the bottom of the tank body 3, and the support 7 is circumferentially distributed around the drain valve 6. The water outlet of the expansion tank is connected to the inlet of the centrifugal pump, and the volume of the expansion tank is 30 m 3 , and the tank body material of the expansion tank is Q345R / Q235. The outlet of the centrifugal pump is connected to the inlet of the soft water cooling pipeline. The top of the vertical cyclone degassing tank is connected to the inlet of the three-way pipe. An automatic exhaust valve 1 - 2 and a manual exhaust valve 1 - 1 are respectively arranged at the two outlets of the three-way pipe. The automatic exhaust valve 1 - 2 and the manual exhaust valve 1 - 1 can be switched according to needs. The automatic exhaust valve 1 - 2 is connected to the first gas alarm, and the manual exhaust valve 1 - 1 is connected to the second gas alarm. Through the first gas alarm or the second gas alarm, it is possible to detect the leakage of the cooling wall in the first time. A drain valve 6 is arranged at the bottom of the vertical cyclone degassing tank. The inner wall of the vertical cyclone degassing tank is sprayed with polyurethane.

[0027] Step 2: When the concentration of CO gas discharged from the vertical cyclone degassing tank is greater than 11%, the first gas alarm or the second gas alarm gives an alarm. At this time, first close the return water valve at the upper end of the branch pipe inside the cooling wall, then close the water inlet valve at the lower end of the branch pipe inside the cooling wall, and then connect a pressure gauge to the bypass valve on the branch pipe inside the cooling wall to monitor the pressure in the pipeline between the return water valve and the water inlet valve. If the pressure in the pipeline between the return water valve and the water inlet valve is 0.45 - 1.1 Mpa, then there is an internal leak in the pipeline between the return water valve and the water inlet valve. An internal leak means that the cooling medium inside the cooling wall leaks from the pipeline or weld to the furnace chamber or the space inside the furnace, rather than directly flowing out of the equipment. The return water valve and the water inlet valve are respectively installed with a return water quick connector and a water inlet quick connector, and both the return water quick connector and the water inlet quick connector are type B quick connectors.

[0028] Online analyze the H2 content in the blast furnace gas discharged from the normal gas outlet channel at the top of the blast furnace, and adjust the fuel ratio according to the following formula: Fuel ratio = [J + (η1 - η0) × 100 × 0.1] + [M + (η1 - η0) × 100 × 0.15 + (∆T - ∆T1) × 0.8], where, J: reference coke ratio, J takes the coke ratio of the 3 smelting cycles closest to the current time, unit: kg / t; M: Benchmark coal ratio. M is the coal ratio in the 1.5 smelting cycles closest to the current time, unit: kg / t. η1: Current value of hydrogen content. It is the H2 content in the blast furnace gas currently discharged from the normal gas outlet channel at the top of the blast furnace, unit: %. η0: Benchmark value of hydrogen content. It is the real-time average value in the 1 smelting cycle closest to the current time, unit: %. ∆T: Current value of the temperature difference between the inlet and outlet water of the cooling stave, unit: °C. ∆T1: Benchmark value of the temperature difference between the inlet and outlet water of the cooling stave. ∆T1 is the real-time average value in the 1 smelting cycle closest to the current time, unit: °C.

[0029] In this embodiment, the benchmark coke ratio J is 341 kg / t, the benchmark coal ratio M is 163.5 kg / t, the current value of hydrogen content η1 is 5.51%, the benchmark value of hydrogen content η0 is 3.12%, the current value of the temperature difference between the inlet and outlet water of the cooling stave ∆T is 7.12 °C, and the benchmark value of the temperature difference between the inlet and outlet water of the cooling stave ∆T1 is 4.52 °C.

[0030] The blast furnace in this embodiment is a large blast furnace with a volume of 5100 m 3 , and the current utilization coefficient is 2.25 m³ / (t·d). In this embodiment, the duration of 1 smelting cycle is 7.5 hours.

[0031] Substitute the benchmark coke ratio J, benchmark coal ratio M, current value of hydrogen content η1, benchmark value of hydrogen content η0, current value of the temperature difference between the inlet and outlet water of the cooling stave ∆T, and benchmark value of the temperature difference between the inlet and outlet water of the cooling stave ∆T1 into the above formula to calculate the fuel ratio: Fuel ratio = [341 + (0.0551 - 0.0312) × 100 × 0.1] + [163.5 + (0.0551 - 0.0312) × 100 × 0.15 + (7.12 - 4.52) × 0.8] ≈ 507.18 kg / t. According to the calculation result, adjust the fuel ratio to 507.18 kg / t. By adjusting the fuel ratio, the reduction of furnace temperature caused by the internal leakage of cooling water is effectively avoided, and the normal operation state in the furnace is maintained.

[0032] Step 3: For the pipeline with internal leakage, redirect the industrial water; for the other pipelines, install crossover pipes to bypass the pipeline with internal leakage, and then resume the soft water cooling. Connect the industrial water to the pipeline with internal leakage using a metal hose. Quick connectors are provided on both sides of the metal hose, and the quick connectors are type A quick connectors. When redirecting the industrial water, insert the type A quick connector at one end of the first metal hose into the groove of the type B quick connector on the inlet valve of the pipeline with internal leakage and then rotate to lock it. Use a sealing ring (such as silicone or rubber) to enhance the airtightness of the connection. Connect the other end of the first metal hose to the industrial water source. Insert the type A quick connector at one end of the second metal hose into the groove of the type B quick connector on the return valve of the pipeline with internal leakage and then rotate to lock it. Use a sealing ring (such as silicone or rubber) to enhance the airtightness of the connection. Connect the other end of the second metal hose to the industrial water storage tank.

[0033] Step 4: Test the CO gas concentration discharged from the vertical cyclone degasser in the BF soft water cooling system again. When the CO gas concentration discharged from the vertical cyclone degasser ≤ 11%, it is determined that the pipeline leak point in the BF soft water cooling system has been eliminated; when the CO gas concentration discharged from the vertical cyclone degasser is greater than 11%, repeat Steps 2 to 4.

[0034] Example 2 A leak detection method for pressure testing and cyclone degassing of a BF soft water cooling system includes the following steps: Step 1: Test the CO gas concentration discharged from the vertical cyclone degasser in the BF soft water closed-loop cooling system. The BF soft water closed-loop cooling system includes several parallel soft water cooling pipelines, which are evenly distributed circumferentially along the inner side of the furnace shell. The soft water cooling pipelines are vertically arranged along the inner side of the furnace shell of the blast furnace. The lower end of the soft water cooling pipeline is the inlet, and the pressure at the inlet of the soft water cooling pipeline is 1.1 MPa. The upper end of the soft water cooling pipeline is the outlet, and the pressure at the outlet of the soft water cooling pipeline is 0.3 MPa. The soft water cooling pipeline includes several series-connected cooling walls, and each cooling wall of the soft water cooling pipeline adopts a "one-string-to-the-top" cooling method. The series-connected cooling walls on the same soft water cooling pipeline penetrate the hearth, bosh, waist, shaft, and throat of the blast furnace from bottom to top. In this example, the "step-by-step" pipeline layout principle is adopted, and no downward detoured pipelines are set.

[0035] The outlet of the soft water cooling pipeline is connected to the inlet of the vertical cyclone degasser through an inlet valve. The vertical cyclone degasser is located at the top of the blast furnace, and the volume of the vertical cyclone degasser is 35m 3. The vertical swirl degassing tank includes a tank body. There is a liquid level line inside the tank body. An inlet is provided at the lower part of the tank body. An inlet valve is set at the inlet. The inlet accesses the tank body from bottom to top. The included angle between the inlet and the tank body is 20°, so that the cooling water flows into the interior of the tank body along the inlet at a flow rate of 7-10 m / s. After the cooling water enters the interior of the tank body along the inlet, it undergoes a swirling motion from bottom to top; an outlet is also provided at the lower part of the tank body. The outlet of the tank body is set on the opposite side of the inlet of the tank body. An outlet valve is set at the outlet. The outlet is connected to the inlet of the expansion tank through the outlet valve. A drain valve is set at the central position of the bottom of the tank body. A support is also set at the bottom of the tank body. The supports are circumferentially distributed around the drain valve. The outlet of the expansion tank is connected to the inlet of the centrifugal pump. The volume of the expansion tank is 30 m 3 , and the tank body material of the expansion tank is Q345R / Q235. The outlet of the centrifugal pump is connected to the inlet of the soft water cooling pipeline. The top of the vertical swirl degassing tank is connected to the inlet of the three-way pipe. An automatic exhaust valve and a manual exhaust valve are respectively set at the two outlets of the three-way pipe. The automatic exhaust valve and the manual exhaust valve can be switched according to needs. The automatic exhaust valve is connected to the first gas alarm, and the manual exhaust valve is connected to the second gas alarm. Through the first gas alarm or the second gas alarm, leakage of the cooling wall can be detected in the first time. A drain valve is set at the bottom of the vertical swirl degassing tank. The inner wall of the vertical swirl degassing tank is sprayed with polyurethane.

[0036] Step 2: When the concentration of CO gas discharged from the vertical swirl degassing tank is greater than 11%, the first gas alarm or the second gas alarm issues an alarm. At this time, first close the return water valve at the upper end of the branch pipe inside the cooling wall, then close the inlet valve at the lower end of the branch pipe inside the cooling wall, and then connect a pressure gauge to the bypass valve on the branch pipe inside the cooling wall to monitor the pressure in the pipeline between the return water valve and the inlet valve. If the pressure in the pipeline between the return water valve and the inlet valve is less than 0.45 MPa, there is an external leak in the pipeline between the return water valve and the inlet valve. An external leak means that the cooling medium leaks from the pipeline or connection part of the cooling wall to the external environment of the equipment. For example, the cooling water seeps out or splashes to the surrounding area from the outer wall of the furnace shell. The return water valve and the inlet valve are respectively installed with a return water quick connector and an inlet quick connector. Both the return water quick connector and the inlet quick connector are type B quick connectors.

[0037] Step 3: For the leaking pipes, redirect the industrial water, and for the rest of the pipes, install cross pipes to bypass the leaking pipes and then resume the soft water cooling. Connect the industrial water to the leaking pipes using metal hoses. Quick connectors are provided on both sides of the metal hoses, and the quick connectors are Type A quick connectors. When redirecting the industrial water, insert the Type A quick connector at one end of the first metal hose into the groove of the Type B quick connector on the inlet valve of the leaking pipe and then rotate to lock it. Use a sealing ring (such as silicone or rubber) to enhance the airtightness of the connection. Connect the other end of the first metal hose to the industrial water source. Insert the Type A quick connector at one end of the second metal hose into the groove of the Type B quick connector on the return valve of the pipe with internal or external leakage and then rotate to lock it. Use a sealing ring (such as silicone or rubber) to enhance the airtightness of the connection. Connect the other end of the second metal hose to the industrial water reservoir.

[0038] Step 4: Test the CO gas concentration in the exhaust from the vertical cyclone degasser in the BF soft water cooling system again. When the CO gas concentration in the exhaust from the vertical cyclone degasser ≤ 11%, it is determined that the pipe leak points in the BF soft water cooling system have been eliminated; when the CO gas concentration in the exhaust from the vertical cyclone degasser is greater than 11%, repeat Steps 2 to 4.

[0039] Example 3 A leak detection method for pressure testing and cyclone degassing of a BF soft water cooling system includes the following steps: Step 1: Test the CO gas concentration in the exhaust from the vertical cyclone degasser in the BF soft water closed-loop cooling system. The BF soft water closed-loop cooling system includes several parallel soft water cooling pipelines, which are evenly distributed circumferentially along the inner side of the furnace shell. The soft water cooling pipelines are vertically arranged along the inner side of the furnace shell of the blast furnace. The lower end of the soft water cooling pipeline is the inlet, and the pressure at the inlet of the soft water cooling pipeline is 1.1 MPa. The upper end of the soft water cooling pipeline is the outlet, and the pressure at the outlet of the soft water cooling pipeline is 0.3 MPa. Each soft water cooling pipeline includes several series-connected cooling walls, and the cooling walls of each soft water cooling pipeline adopt the "one string to the top" cooling method. The series-connected cooling walls on the same soft water cooling pipeline penetrate the hearth, bosh, waist, shaft and throat of the blast furnace from bottom to top. In this example, the "step by step" pipe layout principle is adopted, and no downward detouring pipelines are set.

[0040] As Figure 3As shown, the outlet of the soft water cooling pipeline is connected to the inlet of the vertical cyclone degassing tank through a water inlet valve. The outlet of the soft water cooling pipeline is also connected to the inlet of the high-pressure booster pump station and the inlet of the medium-pressure booster pump station. The high-pressure booster pump station and the medium-pressure booster pump station are arranged in parallel. Among them, the outlet of the high-pressure booster pump station is connected to the inlet of the cooling pipeline of the tuyere small sleeve, and the outlet of the cooling pipeline of the tuyere small sleeve is connected to the inlet of the vertical cyclone degassing tank; the outlet of the medium-pressure booster pump station is connected to the inlet of the cooling pipeline of the hot blast valve, the inlet of the cooling pipeline of the tuyere middle sleeve, and the inlet of the cooling pipeline of the tuyere straight blowpipe. The outlet of the cooling pipeline of the hot blast valve, the outlet of the cooling pipeline of the tuyere middle sleeve, and the outlet of the cooling pipeline of the tuyere straight blowpipe are connected to the inlet of the vertical cyclone degassing tank. The cooling pipelines of the hot blast valve, the tuyere middle sleeve, and the tuyere straight blowpipe are arranged in parallel. The vertical cyclone degassing tank is located at the top of the blast furnace, and the volume of the vertical cyclone degassing tank is 35m 3 . The vertical cyclone degassing tank includes a tank body. There is a liquid level line inside the tank body. The water inlet is arranged at the lower part of the tank body. A water inlet valve is arranged at the water inlet. The water inlet accesses the tank body from bottom to top. The included angle between the water inlet and the tank body is 20°, so that the water flow of the cooling water enters the inside of the tank body along the water inlet at a flow rate of 7-10m / s. After the cooling water enters the inside of the tank body along the water inlet, it generates a swirling motion from bottom to top; the lower part of the tank body is also provided with a water outlet. The water outlet of the tank body is arranged on the opposite side of the water inlet of the tank body. A water outlet valve is arranged at the water outlet. The water outlet is connected to the inlet of the expansion tank through the water outlet valve. A blowdown valve is arranged at the central position of the bottom of the tank body. A support is also arranged at the bottom of the tank body. The support is circumferentially distributed around the blowdown valve. The outlet of the expansion tank is connected to the inlet of the centrifugal pump in the main pump station. The volume of the expansion tank is 30m 3 , and the tank body material of the expansion tank is Q345R / Q235. The outlet of the centrifugal pump is respectively connected to the inlet of the soft water cooling pipeline through the bottom water cooling pipe of the furnace and the cooling wall water cooling pipe. The top of the vertical cyclone degassing tank is connected to the inlet of the three-way pipe. An automatic exhaust valve and a manual exhaust valve are respectively arranged at the two outlets of the three-way pipe. The automatic exhaust valve and the manual exhaust valve can be switched according to needs. The automatic exhaust valve is connected to the first gas alarm instrument, and the manual exhaust valve is connected to the second gas alarm instrument. Through the first gas alarm instrument or the second gas alarm instrument, it is possible to detect the leakage of the cooling wall in the first time. A blowdown valve is arranged at the bottom of the vertical cyclone degassing tank. The inner wall of the vertical cyclone degassing tank is sprayed with polyurethane.

[0041] Step 2: When the CO gas concentration discharged from the vertical cyclone degassing tank is greater than 11%, the first gas alarm or the second gas alarm gives an alarm. At this time, first close the return water valve at the upper end of the branch pipe inside the cooling stave, then close the water inlet valve at the lower end of the branch pipe inside the cooling stave, and then connect a pressure gauge to the bypass valve on the branch pipe inside the cooling stave to monitor the pressure in the pipe between the return water valve and the water inlet valve. If the pressure in the pipe between the return water valve and the water inlet valve is 0.45 - 1.1 Mpa, there is an internal leak in the pipe between the return water valve and the water inlet valve. Internal leak means that the cooling medium inside the cooling stave leaks from the pipe or weld to the furnace chamber or the internal space of the furnace, rather than directly flowing out of the equipment. The return water valve and the water inlet valve are respectively installed with a return water quick connector and a water inlet quick connector, and both the return water quick connector and the water inlet quick connector are type B quick connectors.

[0042] Online analyze the H2 content in the blast furnace gas discharged from the normal gas outlet channel at the top of the blast furnace, and adjust the fuel ratio according to the following formula: Fuel ratio = [J + (η1 - η0) × 100 × 0.1] + [M + (η1 - η0) × 100 × 0.15 + (∆T - ∆T1) × 0.8], where, J: reference coke ratio, J takes the coke ratio of the nearest 3 smelting cycles to the current time, unit: kg / t; M: reference coal ratio, M takes the coal ratio of the nearest 1.5 smelting cycles to the current time, unit: kg / t; η1: current value of hydrogen content, the H2 content in the blast furnace gas currently discharged from the normal gas outlet channel at the top of the blast furnace, unit: %; η0: reference value of hydrogen content, takes the real-time average value of the nearest 1 smelting cycle to the current time, unit: %; ∆T: current value of the temperature difference between the inlet and outlet water of the cooling stave, unit: °C; ∆T1: reference value of the temperature difference between the inlet and outlet water of the cooling stave, ∆T1 takes the real-time average value of the nearest 1 smelting cycle to the current time, unit: °C.

[0043] In this embodiment, the reference coke ratio J is 351 kg / t, the reference coal ratio M is 158.6 kg / t, the current value of hydrogen content η1 is 6.12%, the reference value of hydrogen content η0 is 3.52%, the current value of the temperature difference between the inlet and outlet water of the cooling stave ∆T is 8.12 °C, and the reference value of the temperature difference between the inlet and outlet water of the cooling stave ∆T1 is 5.01 °C.

[0044] The blast furnace in this embodiment is 3800 m 3 blast furnace, the current utilization coefficient is 3.11 m³ / (t·d). In this embodiment, the duration of 1 smelting cycle is 7.0 hours.

[0045] Substitute the reference coke ratio J, reference coal ratio M, current hydrogen content η1, reference hydrogen content η0, current temperature difference ∆T between the inlet and outlet water of the cooling stave, and reference temperature difference ∆T1 between the inlet and outlet water of the cooling stave into the above formula to calculate the fuel ratio: Fuel ratio = [351 + (0.0612 - 0.0352) × 100 × 0.1] + [158.6 + (0.0612 - 0.0352) × 100 × 0.15 + (8.12 - 5.01) × 0.8] ≈ 512.74 kg / t, According to the calculation result, adjust the fuel ratio to 512.74 kg / t. By adjusting the fuel ratio, the reduction of the furnace temperature caused by the internal leakage of cooling water is effectively avoided, and the normal operation state of the furnace is maintained.

[0046] Step 3: Redirect the industrial water to the leaking pipeline, and redirect the other pipelines to cross over the leaking pipeline and restore the soft water cooling. Use a metal hose to introduce industrial water into the leaking pipeline. A quick connector is provided on both sides of the metal hose, and the quick connector is a Type A quick connector. When redirecting the industrial water, insert the Type A quick connector at one end of the first metal hose into the groove of the Type B quick connector on the inlet valve of the leaking pipeline and then rotate to lock it. Use a sealing ring (such as silica gel or rubber) to increase the airtightness of the connection. Connect the other end of the first metal hose to the industrial water source. Insert the Type A quick connector at one end of the second metal hose into the groove of the Type B quick connector on the return valve of the leaking pipeline and then rotate to lock it. Use a sealing ring (such as silica gel or rubber) to increase the airtightness of the connection. Connect the other end of the second metal hose to the industrial water reservoir.

[0047] Step 4: Test the concentration of CO gas discharged from the vertical cyclone degassing tank in the blast furnace soft water cooling system again. When the concentration of CO gas discharged from the vertical cyclone degassing tank ≤ 11%, it is determined that the leak point of the blast furnace soft water cooling system pipeline has been eliminated; when the concentration of CO gas discharged from the vertical cyclone degassing tank is greater than 11%, repeat Steps 2 to 4.

[0048] Although the present invention has been described in detail by referring to the accompanying drawings and in combination with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, those of ordinary skill in the art can make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions should all be within the scope of the present invention / Any person familiar with the technical field of the present invention can easily think of changes or substitutions within the technical scope disclosed by the present invention, and all should be covered within the protection scope of the present invention.

Claims

1. A leak detection method for swirl degassing of a blast furnace soft water cooling system, characterized in that, It includes the following steps: Step 1: Test the CO gas concentration discharged from the vertical cyclone degassing tank in the BF soft water cooling system; Step 2: When the CO gas concentration discharged from the vertical cyclone degassing tank is greater than 11%, first close the return water valve, then close the inlet water valve, and then monitor the pressure in the pipeline between the return water valve and the inlet water valve. If the pressure in the pipeline between the return water valve and the inlet water valve ≥ 1.1 MPa, the pipeline between the return water valve and the inlet water valve is not damaged; if the pressure in the pipeline between the return water valve and the inlet water valve is less than 1.1 MPa, there is internal leakage or external leakage in the pipeline between the return water valve and the inlet water valve; Step 3: For the pipeline with internal leakage or external leakage, divert industrial water, and for the remaining pipelines, install crossover pipes to cross over the pipeline with internal leakage or external leakage, and resume soft water cooling; Step 4: Test the CO gas concentration discharged from the vertical cyclone degassing tank in the BF soft water cooling system again. When the CO gas concentration discharged from the vertical cyclone degassing tank ≤ 11%, it is determined that the pipeline leak point in the BF soft water cooling system has been eliminated; when the CO gas concentration discharged from the vertical cyclone degassing tank is greater than 11%, repeat Steps 2 to 4.

2. The leak detection method according to claim 1, wherein In Step 1, the BF soft water cooling system is a BF soft water closed-loop cooling system, which includes several parallel soft water cooling pipelines circumferentially distributed inside the furnace shell of the BF.

3. The leak detection method according to claim 2, wherein The soft water cooling pipeline includes several series-connected cooling walls; the soft water cooling pipeline stands vertically inside the furnace shell of the BF, with the lower end of the soft water cooling pipeline as the inlet and the upper end as the outlet.

4. The leak detection method according to claim 3, wherein In Step 1, the vertical cyclone degassing tank is located at the top of the BF.

5. The leak detection method according to claim 4, wherein The vertical cyclone degassing tank includes a tank body. An inlet is provided at the lower part of the tank body, and the inlet accesses the tank body from bottom to top, so that the water flow enters the interior of the tank body along the inlet and generates a swirling motion from bottom to top; an outlet is also provided at the lower part of the tank body, and the outlet is connected to the inlet of the expansion tank. The outlet of the expansion tank is connected to the inlet of the centrifugal pump, and the outlet of the centrifugal pump is connected to the inlet of the soft water cooling pipeline.

6. The leak detection method according to claim 5, characterized in that, The water flow enters the interior of the tank body along the inlet at a flow rate of 7 - 10 m / s.

7. The leak detection method according to claim 1, characterized in that In Step 2, the pipeline between the return water valve and the inlet water valve is a branch pipe inside the cooling wall.

8. The leak detection method according to claim 1, characterized in that, In Step 2, if the pressure in the pipeline between the return water valve and the inlet water valve is 0.45 - 1.1 Mpa, there is internal leakage in the pipeline between the return water valve and the inlet water valve; if the pressure in the pipeline between the return water valve and the inlet water valve is less than 0.45 MPa, there is external leakage in the pipeline between the return water valve and the inlet water valve.

9. The leak detection method according to claim 7, characterized in that, When there is internal leakage in the pipeline between the return water valve and the inlet water valve, online analyze the H2 content in the BF gas discharged from the normal gas outlet channel at the top of the BF furnace, and adjust the fuel ratio according to the following formula: Fuel ratio = [J + (η1 - η0) × 100 × 0.1] + [M + (η1 - η0) × 100 × 0.15 + (∆T - ∆T1) × 0.8], where, J: reference coke ratio, J takes the coke ratio of 3 smelting cycles, unit: kg / t; M: reference coal ratio, M takes the coal ratio of 1.5 smelting cycles, unit: kg / t; η1: The current value of hydrogen content, which is the H2 content in the blast furnace gas discharged from the normal gas outlet channel at the top of the blast furnace, unit: %; η0: The reference value of hydrogen content, which is the real-time average value of one smelting cycle, unit: %; ∆T: The current value of the temperature difference between the inlet and outlet water of the cooling stave, unit: °C; ∆T1: The reference value of the temperature difference between the inlet and outlet water of the cooling stave. ∆T1 is the real-time average value of one smelting cycle, unit: °C.

10. The leak detection method according to claim 1, wherein, In step three, industrial water is introduced into the pipeline with internal or external leakage using a metal hose, and quick connectors are provided on both sides of the metal hose.

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