A blast furnace coal gun, a blocking prevention device thereof and a detection and control method thereof

Abstract

The application discloses a blast furnace coal gun and a blocking prevention device and detection and control method thereof. The device comprises a front-end pipe, a blowing branch pipe and a tail pipe. The front-end pipe and the tail pipe are connected in an axial through manner. The blowing branch pipe is connected with the tail pipe in a through manner. The blowing branch pipe and the tail pipe are provided with stop valves. The method comprises the following steps: a pressure sensor is arranged in the front-end pipe of the device, a camera is arranged in the tuyere straight blowing pipe, and an alarm is connected through a pressure monitoring system. A starting time t1 corresponds to a coal gun pressure P1. After a time period Δt, a time t2 corresponds to a coal gun pressure P2. P2-P1=ΔP is set. When ΔP is greater than a set value, an abnormal state is triggered, and an alarm state is triggered. After the coal gun pressure value alarm, whether the coal gun is normally blown in the tuyere picture is observed through the tuyere camera, so that the working state of the coal gun is monitored in real time. The application can realize real-time monitoring of the coal gun spraying state, timely alarm of the abnormal state, and simple, convenient cleaning and maintenance of the coal gun blocking prevention device.

Description

Technical Field

[0001] This invention relates to blast furnace coal lances and their anti-blocking devices and detection and control methods, belonging to the technical field of blast furnace coal injection. Background Technology

[0002] With increasingly stringent environmental protection and ironmaking cost control requirements, blast furnace production urgently needs a cheap and readily available raw material to alleviate the pressure of coke consumption. Pulverized coal injection (PCI) is a technology that injects mixed pulverized coal into the blast furnace through the tuyeres to partially replace coke in reducing ore and for combustion heat release. PCI not only reduces pig iron smelting costs but also improves the energy consumption structure of blast furnaces and reduces environmental pollution caused by coking.

[0003] The pulverized coal used for blast furnace injection is not only diverse in type but also varies greatly in quality; it generally has characteristics such as high impurities, coarse particle size, and high moisture content. This leads to problems such as lance blockage, reduced pulverized coal injection volume, uneven injection, and instability. Lance blockage reduces the amount of pulverized coal used to replace coke in the blast furnace, resulting in reduced calorific value entering the blast furnace, causing fluctuations in the composition of molten iron, and in severe cases, affecting the blast furnace condition.

[0004] Patent CN207699616U discloses a blast furnace pulverized coal lance unblocking device, which uses the pressure of hot blast from the blast furnace to blow out the blockage from the three-way pipe and uses a cloth bag to collect the blockage and pulverized coal, achieving the effect of uninterrupted blasting to clear the blocked pulverized coal lance. However, the hot blast from the blast furnace can easily cause the metal parts of the pulverized coal lance to deform due to heat, and there are potential safety hazards. Furthermore, this method does not involve automatic detection of pulverized coal lance blockage, and it is unclear under what circumstances the unblocking operation needs to be initiated.

[0005] Increasing the amount of pulverized coal injected into blast furnaces can effectively reduce coke consumption, thereby lowering production costs and reducing environmental pollution. To ensure a stable and high level of pulverized coal injection in blast furnaces, the continuous and stable operation of the coal lances is crucial. Therefore, quickly identifying whether the coal lances are injecting coal normally and rapidly clearing blockages are key aspects of pulverized coal injection technology. Currently, blast furnaces generally rely on manual observation of tuyeres video footage and on-site inspections to determine if the coal lances are blocked, which makes it difficult to detect blockages in the first instance. Summary of the Invention

[0006] To address the aforementioned problems, this invention discloses a blast furnace coal lance, its anti-clogging device, and its detection and control method. It provides a method for rapidly identifying blast furnace coal lance blockages, and also provides a coal lance anti-clogging device and a clearing method, achieving rapid identification and resolution without affecting normal blast furnace production. The specific technical solution is as follows: A blast furnace coal gun anti-blocking device includes a front end pipe (1), a purge branch pipe (2) and a tail end pipe (3). The front end pipe (1) and the tail end pipe (3) are axially connected. The diameter of the front end pipe (1) is larger than the diameter of the tail end pipe (3). The purge branch pipe (2) is installed on the side wall of the tail end pipe (3) near the front end pipe (1). The purge branch pipe (2) is equipped with a shut-off valve, and the tail end pipe is also equipped with a shut-off valve (4).

[0007] Furthermore, the connection between the front end tube (1) and the tail end tube (3) is in the shape of a step shoulder, and the front end tube (1) and the tail end tube (3) are integrally formed.

[0008] Furthermore, several pressure sensors (5) are evenly arranged on the inner circumference of the front end tube (1).

[0009] Furthermore, the front end pipe (1) is connected to the injection branch pipe (6), and the tail end pipe (3) is connected to the tail end of the coal gun (7).

[0010] A blast furnace lance equipped with a blast furnace lance anti-blocking device includes a direct blowing pipe (8), the front end of which is a coal injection port (12), and the rear end is connected to an air inlet pipe (9). The air inlet pipe (9) has an air inlet (10), and an air inlet camera (11) is installed at the end of the air inlet pipe (9) away from the direct blowing pipe (8). One end of the injection branch pipe (6) is connected to the front end pipe (1), and the other end is connected to the coal injection distributor. The tail pipe (3) is connected to the tail of the coal gun (7), and the head of the coal gun (7) is placed in the coal injection port (12).

[0011] The detection and control methods for blast furnace coal lances include the following steps: Step 1: Fix the blast furnace coal gun anti-blocking device between the coal gun and the coal injection distributor, connect the front end pipe (1) to the injection branch pipe (6), connect the tail pipe (3) to the tail of the coal gun, and close the valve of the purging branch pipe (2). Step 2: Install multiple pressure sensors on the inner wall of the front end tube (1), the pressure sensors are connected to the PLC controller, and the PLC controller is connected to the alarm. Step 3: The front end of the air inlet pipe (9) is connected to the direct blowing pipe (8), and the air outlet camera (11) is set at the tail end. There is continuous air supply in front of the camera. The camera is set at the tail end of the direct blowing pipe. Since there is continuous air supply in front of the camera, there is no need to worry about the camera being blocked or contaminated. Step 4: Coal gun pressure detection and alarm: A fixed time period Δt is set. The shorter the time interval, the more timely the abnormal judgment. The starting time t1 corresponds to the coal gun pressure P1. After the time period Δt, the time is t2, and the corresponding coal gun pressure is P2. Let P2-P1=ΔP. When ΔP is greater than the set value, it is an abnormal state and an alarm is triggered. After the coal gun pressure value alarm is triggered, the coal gun tail is observed in the air vent camera to see if it is spraying normally, thereby monitoring the working status of the coal gun in real time. Step 5: Deactivate the alarm: Disconnect the front end pipe (1) from the blow-off branch pipe, open the shut-off valve of the blow-off branch pipe (2), close the shut-off valve (4) of the tail pipe (3), spray high-pressure gas into the blow-off branch pipe (2) to blow away the blockage in the front end pipe (1), check that the front end pipe (1) is unobstructed, then reconnect the front end pipe (1) to the blow-off branch pipe and continue working.

[0012] Furthermore, the specific process of coal gun pressure detection in step 4 is as follows: Powdered coal enters through the front end pipe of the anti-clogging device and flows to the tail end pipe, then is ejected from the connection port between the tail end pipe and the coal gun. This process causes a change in the mass of powdered coal in the anti-clogging device. Solid density is related to pressure. The formula for solid pressure is P=F / S=G / S=mg / S=ρVg / S. When the gravitational acceleration g, solid volume V, and contact area S are the same, the solid pressure P is proportional to the solid density ρ. If the connection port is blocked while the volume of the front-end pipe remains constant, the density of the coal powder in the front-end pipe will change, which will lead to a change in the pressure in the front-end pipe: dp / dρ=E / P (1-1). The pressure change of pulverized coal is directly proportional to the density change, with a proportionality coefficient of E / ρ, where ρ is the density of pulverized coal and E is the elastic modulus. Its relationship with pressure is: E=f(P) (1-2). Substituting equation (1-2) into equation (1-1), we get: dp / dρ = f(P) / ρ (1-3); Solving differential equation (1-3) yields the functional relationship between pressure and density. When the connection port of the front pipe of the anti-blocking device is blocked, coal powder accumulates inside the front pipe, leading to an increase in coal powder density. According to the pressure-density relationship obtained from equation (1-3), it can be known that the pressure in the front pipe of the anti-blocking device changes.

[0013] Furthermore, the pressure sensor collects the sum of the pressures of nitrogen, air, and pulverized coal.

[0014] The working principle of this invention is: During normal coal injection, the tuyere camera should show a clear area of ​​black coal dust at the coal gun outlet, and this area should be in a state of slight fluctuation. When the tuyere camera shows no black coal dust area or only shows the coal gun without coal dust being ejected, it indicates a coal injection malfunction. At this time, the coal gun pressure information can be used to determine whether the coal gun is blocked.

[0015] The beneficial effects of this invention are: This invention can quickly identify abnormal working conditions of coal guns by detecting abnormal coal gun pressure values, thereby avoiding delays in detecting blocked coal guns due to untimely manual observation and preventing abnormal furnace temperatures that could affect furnace conditions. The coal gun anti-blockage device can effectively reduce the failure rate of coal guns caused by blockages, facilitate quick cleaning, avoid affecting blast furnace conditions, and help reduce the labor intensity of on-site personnel. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the coal gun anti-clogging device of the present invention. Figure 2 This is a diagram showing the normal operating state of the coal gun anti-clogging device of the present invention. Figure 3 This is a schematic diagram of the purging state of the coal gun anti-clogging device of the present invention. Figure 4 This is a schematic diagram of the blast furnace coal lance of the present invention. Figure 5 This is a diagram showing the pressure variation of a coal gun blockage according to an embodiment of the present invention. Figure 6 This is a camera image of a normal pulverized coal injection duct according to an embodiment of the present invention. List of reference numerals in the attached diagram: 1—front end pipe, 2—purging branch pipe, 3—tail end pipe, 4—stop valve, 5—pressure sensor, 6—injection branch pipe, 7—coal gun, 8—direct injection pipe, 9—air inlet pipe, 10—air inlet, 11—air outlet camera, 12—coal injection port. Detailed Implementation

[0017] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0018] Combined with appendix Figure 1 As can be seen, this coal gun anti-clogging device consists of a front-end pipe 1, a tail pipe 3, and a purging branch pipe 2, each with a different diameter. The purpose of the different diameters of the front and tail pipes is to prevent large coal dust or foreign objects from entering the smaller-diameter tail end, causing the blockage to remain at the larger-diameter front end. When the coal gun is operating normally, if... Figure 2 As shown, the shut-off valve of the anti-blocking device purge branch pipe 2 is closed. When the coal gun is blocked, as... Figure 3Remove the anti-blocking device, close the shut-off valve 4 of the tailpipe 3, open the shut-off valve of the purge branch pipe 2, and blow room temperature gas into the purge branch pipe 2 to remove the blockage from the large-diameter front end. After clearing the blockage, reinstall the anti-blocking device. This achieves rapid identification and quick clearing of blocked coal guns without affecting their operation.

[0019] See Figure 4 The blast furnace coal lance of the present invention includes a direct injection pipe 8, the front end of which is a coal injection port 12, and the rear end is connected to an air inlet pipe 9. The air inlet pipe 9 has an air inlet 10, and an air inlet camera 11 is installed at the end of the air inlet pipe 9 away from the direct injection pipe 8. One end of the injection branch pipe 6 is connected to the front end pipe 1, and the other end is connected to the coal injection distributor. The tail pipe 3 is connected to the tail of the coal lance 7, and the head of the coal lance 7 is placed in the coal injection port 12.

[0020] The injection branch pipe 6 is connected to the front end pipe 1 by a threaded connection, a snap-fit ​​connection, or other connection methods. The tail pipe 3 is connected to the coal receiving gun 7 by a threaded connection, a snap-fit ​​connection, or other connection methods.

[0021] The present invention provides a method for detecting and controlling blast furnace coal lances, comprising the following steps: Step 1: Fix the blast furnace coal gun anti-blocking device between the coal gun and the coal injection distributor, connect the front end pipe 1 to the injection branch pipe 6, connect the tail pipe 3 to the tail of the coal gun, and close the valve of the purging branch pipe 2. Step 2: Install multiple pressure sensors on the inner wall of the front-end tube 1. The pressure sensors are connected to the PLC controller, and the PLC controller is connected to the alarm. The pressure sensors are high-temperature resistant and wear-resistant. They are evenly distributed in the front-end tube of the anti-clogging device by welding. The specific number of sensors is determined according to the actual size of the device. The number of sensors should ensure that the collected data meets the usage conditions.

[0022] Step 3: The front end of the air inlet pipe 9 is connected to the direct blowing pipe 8, and the rear end is equipped with an air outlet camera 11. There is continuous air supply in front of the camera. The camera is located at the rear of the direct blowing pipe. Since there is continuous air supply in front of the camera, there is no need to worry about the camera being blocked or contaminated.

[0023] Step 4: Coal gun pressure detection and alarm: Powdered coal enters through the front end pipe of the anti-clogging device and flows to the tail end pipe, then is ejected from the connection port between the tail end pipe and the coal gun. This process causes a change in the mass of powdered coal in the anti-clogging device. Solid density is related to pressure. The formula for solid pressure is P=F / S=G / S=mg / S=ρVg / S. When the gravitational acceleration g, solid volume V, and contact area S are the same, the solid pressure P is proportional to the solid density ρ. If the connection port is blocked while the volume of the front-end pipe remains constant, the density of the coal powder in the front-end pipe will change, which will lead to a change in the pressure in the front-end pipe: dp / dρ=E / P (1-1). The pressure change of pulverized coal is directly proportional to the density change, with a proportionality coefficient of E / ρ, where ρ is the density of pulverized coal and E is the elastic modulus. Its relationship with pressure is: E=f(P) (1-2). Substituting equation (1-2) into equation (1-1), we get: dp / dρ = f(P) / ρ (1-3); Solving differential equation (1-3) yields the functional relationship between pressure and density. When the connection port of the front pipe of the anti-blocking device is blocked, coal powder accumulates inside the front pipe, leading to an increase in coal powder density. According to the pressure-density relationship obtained from equation (1-3), it can be known that the pressure in the front pipe of the anti-blocking device changes.

[0024] A fixed time period Δt is set, in seconds or minutes. The shorter the time interval, the more timely the anomaly detection. The starting time t1 corresponds to the coal gun pressure P1, in MPa or KPa. After the time period Δt, the time is t2, corresponding to the coal gun pressure P2. Let P2-P1=ΔP. When ΔP is greater than the set value, it is an abnormal state and an alarm is triggered. After the coal gun pressure value alarm, the tail of the coal gun (coal powder injection outlet) in the air vent camera is observed to see if it is spraying normally, thereby monitoring the working status of the coal gun in real time. Step 5: Clear the alarm: Disconnect the front end pipe 1 from the blow-off branch pipe, open the shut-off valve of the blow-off branch pipe 2, close the shut-off valve 4 of the tail pipe 3, spray high-pressure gas into the blow-off branch pipe 2 to clear the blockage in the front end pipe 1, check that the front end pipe 1 is unobstructed, then reconnect the front end pipe 1 to the blow-off branch pipe and continue working.

[0025] The pressure sensor collects the total pressure of nitrogen, air, and pulverized coal. An alarm value is set based on a total pressure ≤ 8 kPa under normal injection conditions. The pressure acquisition time interval is set to seconds or minutes depending on the actual situation. The preset pressure change warning value is determined based on historical data and actual operating conditions.

[0026] The coal injection flow rate of the coal gun is adjusted in real time according to the actual working conditions during the production process, and is measured at the coal injection main pipe.

[0027] The method of this invention: Coal gun anti-clogging detection includes methods such as coal gun pressure monitoring and alarm, vent observation and identification, and on-site inspection confirmation. First, the coal gun pressure signal is collected and calculated by a computer. When the coal gun pressure change exceeds a preset value, an alarm function is triggered (voice alarm) and displayed on the operating system screen (screen pop-up). After receiving the abnormal pressure alarm, the operator can observe whether the coal gun with abnormal pressure is clogged through the vent coal spray screen. If the coal gun spraying is abnormal, the operator should promptly contact the site for confirmation and cleaning. Figure 5The pressure change before and after the coal lance of a blast furnace becomes clogged is shown. Normally, the pressure of pulverized coal injection is 7 kPa. When the lance becomes clogged, the pressure increases to 14 kPa, a pressure change of 7 kPa. The highest pressure difference before the clog was approximately 12 kPa. If the preset pressure change warning value is 5 kPa, then this situation can be identified as coal lance clogged. (Combined with...) Figure 6 Observe whether the corresponding coal gun screen is indeed not spraying coal. If so, contact the site to confirm through the observation hole of the air vent and take measures to clear the blockage.

[0028] The technical means disclosed in this invention are not limited to those disclosed above, but also include technical solutions composed of any combination of the above technical features.

[0029] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A blast furnace coal lance anti-blocking device, characterized in that, It includes a front end pipe (1), a purge branch pipe (2) and a tail end pipe (3). The front end pipe (1) and the tail end pipe (3) are axially connected. The diameter of the front end pipe (1) is larger than the diameter of the tail end pipe (3). The purge branch pipe (2) is installed on the side wall of the tail end pipe (3) near the front end pipe (1). The purge branch pipe (2) is equipped with a shut-off valve. The tail end pipe is also equipped with a shut-off valve (4). The connection between the front end tube (1) and the tail end tube (3) is in the shape of a step shoulder, and the front end tube (1) and the tail end tube (3) are integrally formed; Several pressure sensors (5) are evenly arranged on the inner circumference of the front end tube (1); The front end pipe (1) is connected to the injection branch pipe (6), and the tail end pipe (3) is connected to the tail end of the coal gun (7).

2. A blast furnace lance equipped with the anti-blocking device for blast furnace lances as described in claim 1, characterized in that, It includes a direct blow pipe (8), the front end of which is a coal injection port (12), and the rear end is connected to an air inlet pipe (9). The air inlet pipe (9) has an air inlet (10), and an air inlet camera (11) is installed at the end of the air inlet pipe (9) away from the direct blow pipe (8). One end of the injection branch pipe (6) is connected to the front end pipe (1), and the other end is connected to the coal injection distributor. The tail pipe (3) is connected to the tail of the coal gun (7), and the head of the coal gun (7) is placed in the coal injection port (12).

3. The detection and control method for blast furnace coal lances according to claim 2, characterized in that, Includes the following steps: Step 1: Fix the blast furnace coal gun anti-blocking device between the coal gun and the coal injection distributor, connect the front end pipe (1) to the injection branch pipe (6), connect the tail pipe (3) to the tail of the coal gun, and close the valve of the purging branch pipe (2). Step 2: Install multiple pressure sensors on the inner wall of the front end tube (1), the pressure sensors are connected to the PLC controller, and the PLC controller is connected to the alarm. Step 3: The front end of the air inlet pipe (9) is connected to the direct blow pipe (8), and the tail end is equipped with an air outlet camera (11). There is continuous air supply in front of the camera. Step 4: Coal gun pressure detection and alarm: A fixed time period Δt is set. The shorter the time interval, the more timely the abnormal judgment. The starting time t1 corresponds to the coal gun pressure P1. After the time period Δt, the time is t2, and the corresponding coal gun pressure is P2. Let P2-P1=ΔP. When ΔP is greater than the set value, it is an abnormal state and an alarm is triggered. After the coal gun pressure value alarm is triggered, the coal gun tail is observed in the air vent camera to see if it is spraying normally, thereby monitoring the working status of the coal gun in real time. The specific process for coal gun pressure testing is as follows: Powdered coal enters through the front end pipe of the anti-clogging device and flows to the tail end pipe, then is ejected from the connection port between the tail end pipe and the coal gun. This process causes a change in the mass of powdered coal in the anti-clogging device. Solid density is related to pressure. The formula for solid pressure is P=F / S=G / S=mg / S=ρVg / S. When the gravitational acceleration g, solid volume V, and contact area S are the same, the solid pressure P is proportional to the solid density ρ. If the connection port is blocked while the volume of the front-end pipe remains constant, the density of the coal powder in the front-end pipe will change, which will lead to a change in the pressure in the front-end pipe: dp / dρ=E / P (1-1). The pressure change of pulverized coal is directly proportional to the density change, with a proportionality coefficient of E / ρ, where ρ is the density of pulverized coal and E is the elastic modulus. Its relationship with pressure is: E=f(P) (1-2). Substituting equation (1-2) into equation (1-1), we get: dp / dρ = f(P) / ρ (1-3); Solving differential equation (1-3) yields the functional relationship between pressure and density. That is, when the connection port of the front pipe of the anti-blocking device is blocked, coal powder accumulates inside the front pipe, resulting in an increase in coal powder density. According to the pressure-density relationship obtained from equation (1-3), it can be known that the pressure in the front pipe of the anti-blocking device changes. The pressure sensor collects the sum of the pressures of nitrogen, air, and pulverized coal. Step 5: Deactivate the alarm: Disconnect the front end pipe (1) from the blow-off branch pipe, open the shut-off valve of the blow-off branch pipe (2), close the shut-off valve (4) of the tail pipe (3), spray high-pressure gas into the blow-off branch pipe (2) to blow away the blockage in the front end pipe (1), check that the front end pipe (1) is unobstructed, then reconnect the front end pipe (1) to the blow-off branch pipe and continue working.

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