Control method for switching dq mode of mulpic cooling system acc

Abstract

The application discloses a kind of MULPIC cooling system ACC switching DQ mode control method, when the water-cooled plate of current steel plate cooling is ACC mode, system control 2#DQ butterfly valve and 3#ACC butterfly valve open, close 1#DQ butterfly valve;After current steel plate tail leaves MULPIC frame and next steel plate is DQ mode, system maintains the opening state of 2#DQ butterfly valve, simultaneously control opens 1#DQ butterfly valve and closes 3#ACC butterfly valve;When 1#DQ butterfly valve is completely opened, start water flow detection, if water flow is abnormal, system sends early warning signal, and operator intervenes processing;If water flow is normal, complete ACC switching to DQ mode control.The application method is switched when cooling mode, 3#ACC butterfly valve is closed and 1#DQ butterfly valve is opened simultaneously controlled, to ensure that 1#DQ butterfly valve is opened in place, avoid DQ water-cooled plate because of no cooling water leads to produce abnormal material, and improve production efficiency.

Description

Technical Field

[0001] This invention belongs to the field of steel production technology, specifically relating to a control method for switching the ACC to DQ mode in a MULPIC cooling system. Background Technology

[0002] Zhanjiang Steel's 4200mm thick plate production line is equipped with a post-rolling MULPIC cooling system for producing TMCP plates, such as... Figure 1 As shown, the water-cooled plate is divided into four sections: A, B, C, and D. Section A is controlled by the main pipe butterfly valve #1 (DQ), section B by the main pipe butterfly valve #2 (DQ), and sections C and D by the main pipe butterfly valve #3 (ACC). The MULPIC cooling water mainly comes from two sources: water from the elevated water tower and high-pressure water pumped by the DQ pump set. The water in the elevated water tower is supplied by the ACC pump. The MULPIC is designed with two cooling modes: ACC (accelerated cooling) and DQ (direct quenching). When producing different grades of steel, the MULPIC cooling mode needs to be switched accordingly. Currently, ACC... When switching to DQ mode, the control logic requires the ACC butterfly valve to be fully closed before running the DQ butterfly valve. This method can meet the production requirement of rolling 20 pieces per hour (i.e., 180s / piece). However, as the rolling pace increases, when the rolling pace is optimized to 140s / piece, the response time of the butterfly valve on the MULPIC begins to show a bottleneck. In production, we found that after switching from ACC to DQ mode according to the original control logic (i.e., closing the ACC butterfly valve fully before running the DQ butterfly valve), the rolled steel plate has already been transported to the pre-straightening machine, but the DQ butterfly valve has not yet opened. At this time, the water supply pressure has risen to 7 BAR, and the water pressure completely blocks the valve plate. The current valve actuator cannot drive the valve plate to open, resulting in no water flow in sections A and B, which leads to abnormal cooling of the current DQ water-cooled plate and cannot meet the production needs on site.

[0003] Therefore, in order to avoid the generation of abnormal materials, operators can only manually intervene in the production plan on site. At the same time, when the production plan includes switching from ACC to DQ water-cooled plates, the operators need to limit the rolling rhythm and confirm that the DQ butterfly valve is fully open before rolling, which seriously restricts the rolling rhythm and affects the cooling efficiency of the water-cooled plates. Summary of the Invention

[0004] This invention provides a control method for switching the ACC to DQ mode in a MULPIC cooling system, which can ensure that the DQ butterfly valve opens on time during mode switching, thereby avoiding the generation of abnormal DQ water-cooled plates and effectively improving the rolling rhythm of the production line.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a control method for switching the ACC to DQ mode in a MULPIC cooling system, characterized in that: when the water-cooled plate currently being cooled is in ACC mode, the system controls the opening of the 2#DQ butterfly valve and the 3#ACC butterfly valve in the manifold, and closes the 1#DQ butterfly valve; when the tail of the current steel plate leaves the MULPIC frame and the next steel plate being delivered is in DQ mode, the system maintains the 2#DQ butterfly valve in the open state, while simultaneously controlling the 1#DQ butterfly valve to open and the 3#ACC butterfly valve to close; when the 1#DQ butterfly valve is fully open, the system automatically starts water flow detection, monitoring the outflow through a flow meter installed at the inlet of section A of the water-cooled plate, comparing the actual flow rate monitored by the flow meter with the rated flow rate set at the inlet of section A of the water-cooled plate, and when the deviation between the actual flow rate and the rated flow rate is greater than or equal to 3%, the water flow is determined to be abnormal, the system issues a warning signal, and the operator intervenes to handle the situation until the water flow rate returns to normal; when the deviation between the actual flow rate and the rated flow rate is less than 3%, the water flow is determined to be normal, and the control of switching from ACC to DQ mode is completed.

[0006] Furthermore, the process of operator intervention includes the following steps: (1) Check whether the DQ pump and related pipelines are normal; if the DQ pump is running normally and there is no water leakage in the pipeline, proceed to step (2); if the DQ pump is not running normally and / or the pipeline is leaking, repair the DQ pump and / or pipeline, and after it is restored to normal, check whether the water flow at the inlet of section A of the water-cooled plate has returned to normal. If the flow has returned to normal, the manual intervention operation is completed; if the flow has not yet returned to normal, proceed to step (2).

[0007] (2) Inspect the 3#ACC butterfly valve to ensure it is closed and complete the manual intervention operation.

[0008] Furthermore, a radar level gauge is installed above the ACC high-level laminar flow tank of the MULPIC cooling system. The tank is equipped with a lower limit water level, an alarm water level, and an upper limit water level. During the intervention of the operator, when the liquid level in the tank rises to the alarm water level, the system issues an alarm signal to inspect the No. 3 ACC butterfly valve. After receiving the signal, the operator executes the above step (2). During the inspection of the No. 3 ACC butterfly valve, when the liquid level in the tank continues to rise to the upper limit water level, the system controls the shutdown of the ACC pump. When the liquid level in the tank falls back to the lower limit water level, the system restarts the ACC pump.

[0009] The beneficial effects of this invention are as follows: When the method of this invention is used, when it is necessary to switch from ACC to DQ mode, the system determines that the tail of the steel plate has exited the MULPIC frame and controls the 3#ACC butterfly valve to close, while simultaneously opening the 1#DQ butterfly valve. The control of the two valves is carried out synchronously, which shortens the switching time between ACC and DQ modes in post-rolling cooling, ensures that the 1#DQ butterfly valve has enough time to open to the correct position, avoids abnormal material formation in DQ water-cooled plates due to lack of cooling water, and improves production efficiency. Attached Figure Description

[0010] Figure 1 This is a schematic diagram showing the arrangement of the water-cooled plates and butterfly valves in the manifold of the cooling system.

[0011] Figure 2 This is a flowchart of the method of the present invention.

[0012] Figure 3 This is a flowchart of the manual intervention operation in this invention.

[0013] Figure 4 The data shows the operating time of butterfly valve #1 when switching from ACC to DQ mode using the traditional control method.

[0014] Figure 5 The figure shows the running time of butterfly valve #1 when switching from ACC to DQ mode according to the control method of this invention. Detailed Implementation

[0015] To enable those skilled in the art to fully understand the technical content described in this invention, the invention will be further described in detail below with reference to specific factual examples.

[0016] like Figure 1 As shown, this invention discloses a control method for switching the ACC to DQ mode in a MULPIC cooling system. The specific process is as follows: When the water-cooled plate of the current steel plate is in ACC mode, the system controls the opening of the 2#DQ butterfly valve and the 3#ACC butterfly valve in the manifold, and closes the 1#DQ butterfly valve; when the tail of the current steel plate leaves the MULPIC frame and the next steel plate is in DQ mode, the system controls the 1#DQ butterfly valve to open quickly, and simultaneously controls the 3#ACC butterfly valve to close.

[0017] Each butterfly valve is equipped with a position detection element. When the position detection element on butterfly valve No. 1 detects that butterfly valve No. 1 is fully open, the system automatically starts water flow detection.

[0018] The specific water flow detection process is as follows: The water output is monitored by a flow meter installed at the inlet of section A of the water-cooled plate. The actual flow rate monitored by the flow meter is compared with the rated flow rate set at the inlet of section A of the water-cooled plate. When the deviation between the actual flow rate and the rated flow rate is greater than or equal to 3%, the water flow rate is determined to be abnormal, the system issues an early warning signal, and the operator intervenes to handle the situation until the water flow rate returns to normal. When the deviation between the actual flow rate and the rated flow rate is less than 3%, the water flow rate is determined to be normal, and the control of switching from ACC to DQ mode is completed.

[0019] like Figure 2 As shown, the process of operator intervention includes the following steps.

[0020] (1) Check whether the DQ pump and related pipelines are normal; if the DQ pump is running normally and there is no water leakage in the pipeline, proceed to step (2); if the DQ pump is not running normally and / or the pipeline is leaking, repair the DQ pump and / or pipeline, and check whether the water flow at the inlet of section A of the water-cooled plate has returned to normal after it is restored to normal. If the flow has returned to normal, complete the manual intervention operation; if the flow has not returned to normal, proceed to step (2).

[0021] (2) Inspect the 3#ACC butterfly valve to ensure it is closed and complete the manual intervention operation.

[0022] Furthermore, a radar level gauge is installed above the ACC high-level laminar flow water tower of the MULPIC cooling system. The water tower is equipped with a lower limit water level, an alarm water level, and an upper limit water level. During operator intervention, when the water level in the tower rises to the alarm water level, the system issues an alarm signal to inspect the #3 ACC butterfly valve. Upon receiving the signal, the operator executes step (2). During the inspection of the #3 ACC butterfly valve, when the water level in the tower continues to rise to the upper limit water level, the system controls the shutdown of the ACC pump, effectively preventing the cooling water in the DQ pipeline from flowing back into the water tower, which could potentially cause cooling water overflow. When the water level in the tower falls back to the lower limit water level, the system restarts the ACC pump.

[0023] Based on the production requirement of a rolling rhythm of 140s / block, the following describes the implementation of ACC switching to DQ mode according to the traditional control method and the control method of this invention. The specific details of the two methods are as follows.

[0024] Traditional ACC-to-DQ control method: After the water-cooled steel plate in ACC mode finishes and leaves the MULPIC area, when the next steel plate is in DQ mode, the system controls the #3 ACC butterfly valve to close completely before issuing the run command to open the #1 DQ butterfly valve. The total time from receiving the DQ mode command to the valve opening is 19.9 seconds. If the rolling rhythm is not manually controlled, the rolled steel plate will have already been transported to the pre-straightening machine before the #1 DQ butterfly valve opens. At this time, the water supply pressure has risen to 7 BAR, and the water pressure completely blocks the valve plate. The current valve actuator cannot drive the valve plate to open, resulting in no water flow in sections A and B, thus causing abnormal cooling of the current DQ water-cooled plate.

[0025] The ACC to DQ switching control method of this invention: After the water-cooled steel plate in ACC mode leaves the MULPIC area, when the next steel plate is in DQ mode, the system controls the 3#ACC butterfly valve to close and simultaneously issues the running command 1#DQ butterfly valve to open. The two operate synchronously. The total time from receiving the DQ mode to the valve operating in place is 9.9 seconds, which fully meets the current rolling rhythm.

[0026] After comparing the two methods above, the control method of this invention allows the closing of the 3#ACC butterfly valve and the opening of the 1#DQ butterfly valve to operate synchronously, shortening the switching time between the ACC and DQ modes of post-rolling cooling, ensuring that the 1#DQ butterfly valve has enough time to open fully, avoiding abnormal material formation in the DQ water-cooled plate due to lack of cooling water, and improving production efficiency.

[0027] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A control method for switching ACC to DQ mode in a MULPIC cooling system, characterized in that: When the water-cooled plate cooling the current steel plate is in ACC mode, the system controls the opening of butterfly valves 2#DQ and 3#ACC in the manifold, and closes butterfly valve 1#DQ. When the tail of the current steel plate leaves the MULPIC frame and the next steel plate is in DQ mode, the system maintains the open state of butterfly valve 2#DQ, while controlling butterfly valve 1#DQ to open and butterfly valve 3#ACC to close. When the #1 DQ butterfly valve is fully opened, the system automatically starts water flow detection. The flow rate is monitored by a flow meter installed at the inlet of section A of the water-cooled plate. The actual flow rate monitored by the flow meter is compared with the rated flow rate set at the inlet of section A of the water-cooled plate. When the deviation between the actual flow rate and the rated flow rate is greater than or equal to 3%, the water flow is determined to be abnormal, the system issues an early warning signal, and the operator intervenes to handle the situation until the water flow rate returns to normal. When the deviation between the actual flow rate and the rated flow rate is less than 3%, the water flow rate is determined to be normal, and the control switch from ACC to DQ mode is completed.

2. The control method for switching ACC to DQ mode in the MULPIC cooling system according to claim 1, characterized in that: The process of operator intervention includes the following steps: (1) Check whether the DQ pump and related pipelines are normal; If the DQ pump is operating normally and there is no leakage in the pipeline, proceed to step (2). If the DQ pump is not operating properly and / or the pipeline is leaking, the DQ pump and / or pipeline should be repaired. After it is restored to normal, check whether the water flow at the inlet of section A of the water-cooled plate has returned to normal. If the flow has returned to normal, the manual intervention operation is completed. If the flow has not yet returned to normal, proceed to step (2). (2) Inspect the 3#ACC butterfly valve to ensure it is closed and complete the manual intervention operation.

3. The control method for switching ACC to DQ mode in the MULPIC cooling system according to claim 2, characterized in that: A radar level gauge is installed above the ACC high-level water tank of the MULPIC cooling system. The water tank is equipped with a lower limit water level, an alarm water level, and an upper limit water level. During the intervention of the operator, when the liquid level in the water tower rises to the alarm level, the system sends an alarm signal to inspect the No. 3 ACC butterfly valve. After receiving the signal, the operator executes the above step (2). During the inspection of the No. 3 ACC butterfly valve, when the liquid level in the water tower continues to rise to the upper limit level, the system controls the shutdown of the ACC pump; when the liquid level in the water tower falls back to the lower limit level, the system restarts the ACC pump.

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