Antifreezing method for cooling water pipe of cooling wall of HyCROF furnace

Abstract

The invention belongs to the technical field of cooling water pipe anti-freezing, and particularly discloses a HyCROF furnace cooling wall cooling water pipe anti-freezing method which comprises the following steps that a main valve of a cooling water pipe is closed, pressure is released to a target pressure range, after natural drainage is conducted in sequence, a PLC controls compressed air to purge a main pipeline of the cooling water pipe, and then the main pipeline of the cooling water pipe is closed; the branch drain valves with qualified humidity are closed according to the humidity of the outlets of the drain valves before secondary purging, then the furnace bottom and the lower area of the furnace body are purged, the PLC controls compressed air to accurately purge the tail end during third purging, and the PLC judges whether purging is qualified or not according to the humidity of the outlets of the drain valves after purging; the sequence, pressure and time of drainage and purging are accurately controlled through a PLC program, the randomness of manual operation is reduced, it is ensured that the purging effect is highly uniform and reliable, and the working efficiency and consistency are improved; the problems that a traditional manual purging method is uneven in purging effect and low in operation efficiency are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cooling water pipe anti-freezing, in particular to a HyCROF furnace cooling wall cooling water pipe anti-freezing method. BACKGROUND

[0002] The HyCROF furnace cooling wall is a core cooling equipment in the blast furnace ironmaking process, which is made of high-strength copper material. It is forcedly cooled by internal circulating water to form a stable "slag skin" in the high-temperature area of the blast furnace bosh, belly, etc., thereby efficiently protecting the furnace shell, prolonging the service life of the blast furnace, and realizing safe and stable operation under high utilization coefficient. The design water flow direction of the blast furnace cooling wall soft water closed circulation system is from the low pressure side to the high pressure side, and from the low temperature side to the high temperature side. The specific path is as follows: the low-temperature soft water is sent out from the cooling water pump house by the circulating water pump, sent to the water inlet header under the furnace body through the water supply main pipe, and then distributed to the bottom water inlet of each section of the cooling wall through the water inlet branch pipe from bottom to top. After absorbing heat in the internal pipe of the cooling wall, the high-temperature return water is collected from the top or upper water outlet to the return water branch pipe, and finally flows into the return water main pipe, relying on the residual pressure to flow to the degassing tank and the cooling tower, and is recycled after being cooled and degassed. In high-cold regions such as Xinjiang, after the HyCROF furnace is stopped in winter, the cooling water pipes of the cooling wall must be completely drained. Due to the phase change characteristics of water, the volume will expand by about 9% when it freezes, and the huge expansion stress will directly cause the internal precision waterway of the high-strength copper material cooling wall to break, and even the whole cooling wall to be scrapped.

[0003] After the blast furnace is completely stopped and the blast is blown off, the traditional method of draining the cooling water pipes of the cooling wall is to first drain the soft water in the cooling water pipes, and then workers hold compressed air hoses and blow compressed air into the return water pipe drain valve of the 16th section of the cooling wall from a higher position, forcing the water to flow in the opposite direction, and finally collecting the water from the first section of the cooling wall at a low place to the water distribution package of the water inlet main pipe and flowing back to the water pump house. In this way, the water pipes are completely drained in winter. However, the traditional operation completely depends on the personal experience and physical strength of the workers, and the workers need to hold the hose one by one for connection. The work is done in a space-limited and complex environment, which is labor-intensive and has safety risks. Secondly, the blowing effect is uneven, and it is difficult to ensure that all residual water in the water pipes is completely drained, which may leave dead angles and cause local freezing hazards. Thirdly, the efficiency is low, and the operation of each section and layer takes a long time, which affects the overall maintenance progress. Finally, the control of compressed air pressure and flow is rough, and there is a potential risk of damaging the precision cooling waterway due to instantaneous high pressure. SUMMARY

[0004] The purpose of the present application is to provide a HyCROF furnace cooling wall cooling water pipe anti-freezing method to solve the problems of uneven blowing effect and low operation efficiency of the traditional manual blowing method.

[0005] To achieve the above objectives, the basic solution provided by this invention is: a method for preventing the cooling water pipes of a HyCROF furnace cooling wall from freezing, comprising the following steps: S1. First, close the main valve of the cooling water pipe and depressurize it to the target pressure range. According to the division of the cooling wall area, connect each branch and valve to the PLC controller. Then, connect the humidity sensor at the outlet of each drain valve to the PLC controller. Perform natural drainage for each branch according to the order of the cooling wall area. S2. After natural drainage, connect the rubber hose and compressed air hose through male and female threads. After connecting, pressurize the cooling water pipe branches in each area to assist drainage. Then, the PLC controller controls the compressed air to perform three purging cycles. S3. The main cooling water pipe is purged for the first time. During purging, the PLC controller controls the purging pressure and time, and at the same time controls the opening of the drain valves of the cooling water pipe branches in each area. S4. Before the second purging, the PLC controller closes the branch drain valve with qualified humidity according to the humidity of the drain valve outlet, and first purges the furnace bottom and the lower part of the furnace body. During the purging, the purging pressure and time are controlled. S5. Branch purging is used during the three purging cycles. The PLC controller controls the compressed air pipe to connect to the purging port at the end of the branch, and accurately purifies the end. The S6.PLC controller uses a humidity sensor to determine whether the purging process is qualified by checking the humidity at the outlet of each drain valve after purging.

[0006] The principle and beneficial effects of this invention are as follows: In implementation, the main valve of the cooling water pipe is first closed and the pressure is released to the target pressure range. The branches and valves of the cooling wall area are connected to the PLC controller. Then, the humidity sensors at the outlets of each drain valve are connected to the PLC controller. After natural drainage according to the area sequence, the rubber hose and compressed air pipe are connected for pressurized drainage. Then, the PLC controller controls the compressed air to purge the main cooling water pipe. At the same time, the drain valves of the cooling water pipe branches in each area are opened. Before the second purging, the drain valves of the branches with qualified humidity are closed according to the humidity at the outlet of the drain valve. The furnace bottom and the lower part of the furnace body are purged first. Branch purging is used in the third purging. The PLC controller controls the compressed air to purify the end precisely. The PLC controller uses the humidity sensor to determine whether the purging is qualified by checking the humidity at the outlet of each drain valve after purging.

[0007] The main valve is closed and pressure is released. The PLC is connected to each valve and humidity sensor according to the area division to complete the sequential natural drainage. Then, the compressed air pipeline is connected to assist drainage by pressurization. The PLC controls the execution of three-stage purging: the first is a full system purging, the second is a key area purging, and the third is a precise end purging. Finally, the PLC automatically determines whether the purging of each branch is qualified based on the data fed back by the humidity sensor. This realizes the full-process automated control from drainage to detection, reduces the randomness of manual operation, ensures the high uniformity and reliability of the purging effect, and improves the efficiency and consistency of operation.

[0008] Option 2, an optimal choice of the basic option, involves a depressurization rate of 0.02-0.03 MPa / min in step S1, a target pressure range of P≤0.1 MPa, a natural drainage time of 30-60 min, and the cooling wall area divided into the furnace top, upper middle part of the furnace body, lower part of the furnace body, and furnace bottom. Slow depressurization avoids water hammer or mechanical stress damage to pipes or connections caused by sudden pressure drops, thus protecting pipeline integrity. Reducing the system pressure to a low-pressure state of ≤0.1 MPa creates stable and safe initial conditions for subsequent drainage, preventing residual water from stagnating under pressure. Setting sufficient natural drainage time according to the regional sequence allows gravity to fully drain the large amount of open water in the main pipeline and high-level branches, significantly reducing the load on subsequent pressurization and purging.

[0009] Option 3, which is the preferred option of the basic option, involves pressurizing the drainage in step S2 at a pressure of 0.15-0.2 MPa for 10-15 minutes. Pressurization is automatically stopped when the pressure is ≥0.2 MPa. The compressed air has a dew point ≤-20℃ and a purity ≥99.5%. This can remove the water film remaining in the low-lying areas, bends, and pipe walls after gravity drainage, improving the thoroughness of drainage. Ensuring that the compressed air has a dew point ≤-20℃ and a purity ≥99.9% reduces the introduction of new moisture or oil and other impurities into the pipeline during the purging process, thus reducing the risk of secondary icing from the source.

[0010] Option 4 is the preferred option of the basic option. In step S3, the initial purging pressure is 0.2-0.3 MPa and the purging time is 20-30 minutes. The residual water and a large amount of moisture in the main pipeline are driven out with stable and sufficient kinetic energy, avoiding water retention due to insufficient pressure or incomplete cleaning due to short time. The programmed control ensures that the purging process is uniform and stable, which can effectively remove water and prevent pressure changes from causing impact damage to the pipeline system.

[0011] Option 5 is an optimal choice of the basic option. In step S4, the secondary purging pressure is 0.35-0.45MPa and the purging time is 15-25min. The secondary purging closes qualified branches based on real-time humidity and focuses on removing stubborn moisture from high-risk areas such as the bottom of the furnace and the lower part of the furnace body that are prone to water accumulation, thereby achieving layered and precise antifreeze protection for the entire cooling system and key parts.

[0012] Option 6, which is the preferred option of the basic option, involves three purging pressures of 0.25-0.3 MPa and a purging time of 5-10 minutes in step S5. By precisely purging the branches at the end and controlling the appropriate pressure and time, the last water film and dead corner moisture remaining in the complex structures such as the end of the branch and bends can be effectively removed, achieving thorough drying of the cooling water circuit. This is the last key guarantee to prevent freezing and cracking in local hidden places.

[0013] Option 7, which is an optimal choice of the basic option, involves step S6. If the relative humidity is ≤5% within 5 minutes, the branch is deemed to have passed the purging process. The PLC controller then controls the drain valve of the branch to close. If the purging fails, the process is repeated in step S3 until the humidity at the drain valve outlet is within acceptable limits. Through real-time and objective humidity monitoring, it is ensured that each branch is completely dry, fundamentally reducing the risk of residual moisture freezing due to human error or oversight. This achieves reliable verification of the antifreeze effect. Detailed Implementation

[0014] The present invention will be further described in detail below through specific embodiments: Example A method for preventing the cooling water pipes of a HyCROF furnace cooling wall from freezing includes the following steps: S1. First, close the main valve of the cooling water pipe and depressurize it to the target pressure range. The depressurization rate is 0.02-0.03MPa / min, and the target pressure range is P≤0.1MPa. According to the division of the cooling wall area, connect each branch and valve to the PLC controller. Then connect the humidity sensor at the outlet of each drain valve to the PLC controller. Perform natural drainage on each branch according to the order of the cooling wall area. The natural drainage time is 30-60min. The cooling wall area is divided into the furnace top, the upper middle part of the furnace body, the lower part of the furnace body, and the furnace bottom. S2. After natural drainage, connect the rubber hose and compressed air hose through male and female threads. After connection, pressurize the cooling water pipe branches in each area to assist drainage. The pressurization pressure is 0.15-0.2MPa, and the pressurization time is 10-15min. When the pressure is ≥0.2MPa, the pressurization will automatically stop. Then, the PLC controller will control the compressed air to perform three purgings. The dew point of the compressed air is ≤-20℃, and the purity is ≥99.5%. S3. For the first time, the main cooling water pipe is purged. During purging, the PLC controller controls the purging pressure to be 0.2-0.3MPa and the purging time to be 20-30min. At the same time, the drain valves of the cooling water pipe branches in each area are opened. S4. Before the second purging, the PLC controller closes the branch drain valve with qualified humidity according to the humidity of the drain valve outlet, and first purifies the furnace bottom and the lower part of the furnace body. During purging, the purging pressure is controlled at 0.35-0.45MPa and the purging time is 15-25min. S5. Branch purging is used during the three purging stages. The PLC controller controls the purging port at the end of the compressed air pipe to connect to the branch. The purging pressure is 0.25-0.3MPa, and the purging time for each stage is 5-10 minutes, ensuring precise purging of the end. S6. The PLC controller uses a humidity sensor to determine whether the purging is qualified by checking the humidity at the outlet of each drain valve after purging. If the relative humidity is ≤5% within 5 minutes, the purging of that branch is qualified and the PLC controller controls the drain valve of that branch to close. If the purging is not qualified, the process will cycle to step S3 to continue purging until the humidity at the outlet of the drain valve is qualified.

[0015] The implementation method of this embodiment is as follows: First, close the main valve of the cooling water pipe and depressurize it to the target pressure range. The depressurization rate is 0.02MPa / min, and the target pressure range is P≤0.1MPa. According to the division of the cooling wall area, connect each branch and valve to the PLC controller. Then connect the humidity sensor at the outlet of each drain valve to the PLC controller. Perform natural drainage on each branch according to the order of the cooling wall area. The natural drainage time is 40min. The cooling wall area is divided into the furnace top, the upper middle part of the furnace body, the lower part of the furnace body, and the furnace bottom. After natural drainage, connect the rubber hose and compressed air hose through male and female threads. After connection, pressurize the cooling water pipe branches in each area to assist drainage. The pressurization pressure is 0.18MPa and the pressurization time is 12min. When the pressure is ≥0.2MPa, the pressurization will automatically stop. Then, the PLC controller will control the compressed air to perform three purgings. The dew point of the compressed air is ≤-20℃ and the purity is ≥99.5%. The main cooling water pipe was purged for the first time. During purging, the PLC controller controlled the purging pressure at 0.2 MPa and the purging time at 24 minutes. At the same time, the drain valves of the cooling water pipe branches in each area were opened. Before the second purging, the PLC controller closed the drain valves of the branches with qualified humidity according to the humidity of the drain valve outlet. The furnace bottom and the lower part of the furnace body were purged first. During the purging, the purging pressure was controlled at 0.4 MPa and the purging time at 21 minutes. The third purging used branch purging. The PLC controller controlled the compressed air pipe to connect to the purging port at the end of the branch. The purging pressure was 0.3 MPa and the purging time for each section was 7 minutes, ensuring precise purging of the end. The PLC controller uses a humidity sensor to determine whether the purging is qualified by checking the humidity at the outlet of each drain valve after purging. If the relative humidity is ≤5% within 5 minutes, the purging of that branch is qualified and the PLC controller controls the drain valve of that branch to close. If the purging is not qualified, the cycle continues to purge the main cooling water pipe until the humidity at the outlet of the drain valve is qualified.

[0016] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for preventing freezing of cooling water pipes in the cooling wall of a HyCROF furnace, characterized in that, Includes the following steps: S1. First, close the main valve of the cooling water pipe and depressurize it to the target pressure range. According to the division of the cooling wall area, connect each branch and valve to the PLC controller. Then, connect the humidity sensor at the outlet of each drain valve to the PLC controller. Perform natural drainage for each branch according to the order of the cooling wall area. S2. After natural drainage, connect the rubber hose and compressed air hose through male and female threads. After connecting, pressurize the cooling water pipe branches in each area to assist drainage. Then, the PLC controller controls the compressed air to perform three purging cycles. S3. The main cooling water pipe is purged for the first time. During purging, the PLC controller controls the purging pressure and time, and at the same time controls the opening of the drain valves of the cooling water pipe branches in each area. S4. Before the second purging, the PLC controller closes the branch drain valve with qualified humidity according to the humidity of the drain valve outlet, and first purges the furnace bottom and the lower part of the furnace body. During the purging, the purging pressure and time are controlled. S5. Branch purging is used during the three purging cycles. The PLC controller controls the purging port at the end of the compressed air pipe to accurately purge the end. The S6.PLC controller uses a humidity sensor to determine whether the purging process is qualified by checking the humidity at the outlet of each drain valve after purging.

2. The method for preventing freezing of cooling water pipes in the cooling wall of a HyCROF furnace according to claim 1, characterized in that, In step S1, the pressure relief rate is 0.02-0.03 MPa / min, the target pressure range is P≤0.1 MPa, the natural drainage time is 30-60 min, and the cooling wall area is divided into the furnace top, the upper middle part of the furnace body, the lower part of the furnace body, and the furnace bottom.

3. The method for preventing freezing of cooling water pipes in the cooling wall of a HyCROF furnace according to claim 1, characterized in that, In step S2, the pressure for pressurizing and draining is 0.15-0.2 MPa, the pressurization time is 10-15 min, and the pressurization is automatically stopped when the pressure is ≥0.2 MPa. The dew point of the compressed air is ≤-20℃ and the purity is ≥99.5%.

4. The method for preventing freezing of cooling water pipes in the cooling wall of a HyCROF furnace according to claim 1, characterized in that, In step S3, the initial purging pressure is 0.2-0.3 MPa, and the purging time is 20-30 min.

5. A method for preventing freezing of cooling water pipes in a HyCROF furnace cooling wall according to claim 1, characterized in that, In step S4, the secondary purging pressure is 0.35-0.45 MPa, and the purging time is 15-25 min.

6. The method for preventing freezing of cooling water pipes in the cooling wall of a HyCROF furnace according to claim 1, characterized in that, In step S5, the purging pressure is 0.25-0.3 MPa for three purging stages, and the purging time for each stage is 5-10 min.

7. A method for preventing freezing of cooling water pipes in a HyCROF furnace cooling wall according to claim 1, characterized in that, In step S6, if the relative humidity is detected to be ≤5% within 5 minutes, the branch is deemed to have passed the purging test, and the PLC controller controls the drain valve of the branch to close. If the purging test fails, the cycle repeats to step S3 to continue purging until the humidity at the drain valve outlet is within acceptable limits.