Blast furnace body water system pressure test leak detection method

Abstract

The invention relates to a blast furnace body water system pressure test leak detection method, which adopts different leak detection pressure test pressures and media according to different pressure test areas, and uses compressed air for preliminary leak detection and treatment in advance according to the time difference between opening of the blast furnace water system and completion of the blast furnace body water system, thereby laying a foundation for subsequent pressure rise leak detection by using cooling water. The high-pressure leak detection and processing time is greatly shortened, and conditions are created for completing leak detection of a furnace body water system in advance and completing projects in advance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of blast furnace smelting, more particularly, it relates to a kind of blast furnace body water system pressure test leak detection method. BACKGROUND

[0002] Blast furnace body water system is the key cooling system for maintaining normal operation of blast furnace, mainly through circulating water cooling furnace structure to prevent high temperature deformation and damage. Blast furnace body water system contains cooling wall structure, specifically, install multiple copper cooling wall inside the furnace body, absorb high temperature heat in the furnace, blast furnace body water system adopts soft water closed cycle system, equipped with plate heat exchanger to replace traditional cooling tower, according to the lift of cooling position to optimize zoning, such as furnace belly, furnace waist and other high temperature zone adopts independent cooling circuit.

[0003] The sealing of blast furnace body water system is directly related to its cooling effect, the traditional blast furnace body water system pressure test leak detection is usually carried out simultaneously with the whole leak detection of blast furnace water system, in the case of multiple pipe head weld, it often needs to be repeatedly tested and treated, which is time-consuming and laborious, and there is a lot of water waste. Therefore, it is necessary to put forward a new pressure test leak detection method. SUMMARY

[0004] In view of the deficiencies in the prior art, the purpose of the present application is to provide a kind of blast furnace body water system pressure test leak detection method, which greatly shortens the high pressure leak detection and treatment time, and creates conditions for completing the blast furnace body water system leak detection and project in advance.

[0005] The above technical purpose of the present application is realized by the following technical scheme: A kind of blast furnace body water system pressure test leak detection method, comprising the following steps: S1, mark each layer of cooling wall water pipe number; S2, before water is passed through blast furnace body, use compressed air to carry out segmented leak detection on the cooling wall and communication pipe which have been constructed; S3, leak detection is carried out on the furnace bottom water cooling pipe system, including leak detection on the furnace bottom water inlet main pipe and leak detection on the recovery main pipe and branch pipe, as follows: S3.1, inject high pressure industrial water from the blowdown valve of the water recovery main pipe, gradually increase the water pressure to the normal production working pressure, check the leakage point and seepage point and mark them, after drainage, carry out repair welding, and then inject water again to ensure that there is no leakage point; S3.2, after the repair of the leakage point and the seepage point is completed, continue to inject water to increase the pressure and keep the pressure, and confirm that there is no sweating and pressure drop; S4, leak detection is carried out on the furnace body water supply main pipe and ring pipe system, as follows: S4.1, inject water from the blowdown valve of the furnace cooling wall water supply ring pipe, and close the exhaust valve of the ring pipe after water is seen from the exhaust valve of the ring pipe; S4.2, gradually water injection to increase pressure to normal production working pressure, continue to carry out leak detection treatment until no leakage and no pressure drop phenomenon occurs; S4.3, continue to increase pressure by water injection, continue leak detection treatment until no leakage and no pressure drop phenomenon occurs; S5, overall pressure test and leak detection of the furnace body water system, as follows: S5.1, fill water from the cooling wall water inlet ring pipe, gradually increase the pressure, close the exhaust valve of each layer platform pipe after the water is seen, when the water pressure drops, detect the leakage points of each layer platform pipe and mark them, and treat them after pressure relief; S5.2, after completing the leakage defect treatment, retest pressure, if the pressure does not drop, the pressure test is qualified.

[0006] In one of the embodiments, in step S2, the step of sectional leak detection is as follows: compressed air is introduced into the completed cooling wall, the outlet valve of the water pipe of each region and the inlet valve and outlet valve of the connecting pipe are closed, the inlet valve and outlet valve of the cooling wall of the region to be detected are opened, and the cooling wall of the same number of water pipes and the cooling wall water channel are connected.

[0007] In one of the embodiments, in step S2, the pressure of the compressed air is controlled at 80-90% of the cooling water pressure during normal production.

[0008] In one of the embodiments, in step S3.2, during the leak detection process, the water injection to increase pressure to 1.8-2.0 times of the normal production working pressure is continued, and the pressure maintaining time is ≥30 min.

[0009] In one of the embodiments, in step S4.2, after the water injection to increase pressure to the normal production working pressure, the leakage-free and pressure-drop-free phenomenon is maintained for ≥30 min, and it is judged that the leak detection treatment is completed.

[0010] In one of the embodiments, in step S4.3, the water injection to increase pressure to 1.8-2.0 times of the normal production working pressure, and the leakage-free and pressure-drop-free phenomenon is maintained for ≥30 min, and it is judged that the pressure test is qualified.

[0011] In one of the embodiments, in step S5.1, the water pressure is increased to 1.2-1.4 times of the normal production working pressure.

[0012] In one of the embodiments, in step S5.2, during the retest pressure, if the pressure does not drop for ≥10 min, the pressure test is qualified.

[0013] In summary, the present application has the following beneficial effects: The present application adopts different leak detection test pressures and media according to different test pressure areas, and uses compressed air to preliminarily detect and treat leaks in advance according to the time difference between the blow-through of the blast furnace water system and the completion of the blast furnace body water system, thereby laying a foundation for subsequent leak detection using cooling water at a higher pressure (higher than the normal production pressure), greatly shortening the high-pressure leak detection and treatment time, and creating conditions for early completion of the blast furnace body water system leak detection and project. DETAILED DESCRIPTION

[0014] The present application will be described in detail below with reference to examples.

[0015] The present application provides a blast furnace body water system pressure test leak detection method, comprising the following steps: S1, marking the water pipe numbers of each layer of cooling wall.

[0016] After the regional cooling wall is installed and the inlet valves, outlet valves, communication pipes and exhaust valves between the layers of cooling wall are all welded, the water pipe numbers of each layer of cooling wall are marked according to the cooling wall construction drawing numbering, so as to be checked one by one during subsequent pressure test leak detection operation, and the leak detection efficiency is ensured.

[0017] S2, before the blast furnace body is watered, using compressed air to segmentally detect the cooling wall and communication pipes which have been constructed.

[0018] In step S2, the segmental detection is based on the construction condition, and the communication pipes between different regions of the cooling wall are respectively provided with exhaust valves and blowdown valves in front and back, the exhaust valve is used as the inlet valve of the communication pipe, the blowdown valve is used as the outlet valve of the communication pipe, the segmental detection of the cooling wall is realized through the inlet valve and the outlet valve, and the compressed air is used to detect each region of the cooling wall. In the traditional blast furnace body water system, the cooling wall of the blast furnace hearth is a whole region, and the inlet valve and the outlet valve are not arranged in front and back of the communication pipe, so that the segmental detection and leak detection cannot be realized.

[0019] Preferably, the step of segmental detection is as follows: the compressed air is introduced into the constructed cooling wall, the outlet valve of the water pipe of each region and the inlet valve and outlet valve of the communication pipe are closed, the inlet valve and outlet valve of the cooling wall of the region to be detected are opened, and the cooling wall of the same number of water pipes and the cooling wall water channel are communicated.

[0020] In the overall construction progress of the blast furnace, the operation of the whole blow-through of the blast furnace water system is relatively complex, and generally lags behind the completion of the cooling wall and the pipeline and valve construction by 7-10 days, or even longer. The present application uses the time difference to preliminarily detect the air tightness of the cooling wall by compressed air, greatly reduces the workload of subsequent water blow-through and pressure increase leak detection, and creates conditions for early completion.

[0021] Compared with the existing leak detection medium, compressed air is used in step S2, which is not limited by water and has little impact on construction. Preferably, the pressure of the compressed air is controlled at 80-90% of the normal production cooling water pressure. If no leakage occurs, the subsequent increase to 100% pressure will also not cause leakage.

[0022] S3, leak detection of the furnace bottom water-cooled pipe system, including leak detection of the furnace bottom water inlet main pipe and leak detection of the recovery main pipe and branch pipes, as follows: S3.1, injecting blast furnace industrial water from the backwater main pipe blowdown valve, gradually increasing the water pressure to the normal production working pressure, checking for leaks and seepage points and marking them, and performing repair welding after draining, and ensuring no leaks after re-injection of water; S3.2, after completing the repair of leaks and seepage points, continue to inject water to increase the pressure and maintain the pressure, and confirm that there is no sweating and no pressure drop.

[0023] In step S3, before pressure testing, it is confirmed that the furnace bottom water inlet main pipe, backwater main pipe and branch pipes are installed, blind plates are installed at the interface with the original old main pipe, exhaust valves are installed at the highest point of the pipes, all branch pipe valves of the backwater main pipe are opened, and the exhaust valves are opened.

[0024] In step S3.2, during the leak detection process, continue to inject water to increase the pressure to 1.8-2.0 times the normal production working pressure, and the pressure maintaining time is ≥30 min.

[0025] S4, leak detection of the furnace body water supply main pipe and ring pipe system, as follows: S4.1, injecting water from the blast furnace cooling wall water supply ring pipe blowdown valve, and closing the ring pipe exhaust valve after water is seen coming out of the ring pipe exhaust valve; S4.2, gradually injecting water to increase the pressure to the normal production working pressure, and continuing leak detection treatment until no leaks and no pressure drop occur; S4.3, continue to inject water to increase the pressure, and continue leak detection treatment until no leaks and no pressure drop occur.

[0026] In step S4, before pressure testing, it is confirmed that the furnace body water system (including the straight blow pipe cooling system) pipe installation is completed, the pipe electrical instrument, pressure gauge for pressure testing, and pressure pump installation are completed; blind plates are installed behind the main pipe valves, and the valves within the pressure testing range are in the open position (the first layer of cooling wall branch pipe water inlet valves are closed, and the first layer of cooling wall branch pipe water inlet valves are closed).

[0027] In step S4.2, after injecting water to increase the pressure to the normal production working pressure, no leaks and no pressure drop occur for a time of ≥30 min, and the leak detection treatment is determined to be complete.

[0028] In step S4.3, the water injection pressure is increased to 1.8-2.0 times of the normal production working pressure, and no leakage and pressure drop phenomenon is maintained for ≥30 min, and it is judged as pressure test qualified.

[0029] S5, the whole furnace body water system pressure test and leak detection, as follows: S5.1, from the cooling wall water ring pipe filling water, gradually increasing the pressure, the exhaust valve of each layer platform pipe is closed after water, when the water pressure drops, detect each layer platform pipe leak point and mark, after pressure relief treatment; S5.2, after the completion of leak defect treatment, re-pressurization, if the pressure is not decreased, then the pressure test is qualified.

[0030] Preferably, in step S5.1, the water pressure is increased to 1.2-1.4 times of the normal production working pressure.

[0031] Preferably, in step S5.2, when re-pressurization, if the pressure is not decreased for ≥10 min, then the pressure test is qualified.

[0032] The present application can be popularized to the same industry large, medium and small repair or new blast furnace furnace body water system pressure test and leak detection, has the advantages of high leak detection efficiency and reliable leak detection quality, and has the guarantee for improving the completion period.

[0033] The above is only the preferred embodiment of the present application, the protection scope of the present application is not only limited to the above-mentioned examples, all technical solutions under the idea of the present application belong to the protection scope of the present application. It should be pointed out that for ordinary skilled in the art, some improvements and decorations without departing from the principles of the present application, these improvements and decorations should also be considered as the protection scope of the present application.

Claims

1. A method for pressure testing and leak detection of a blast furnace body water system, characterized in that, Includes the following steps: S1. Label the cooling wall water pipe numbers for each layer; S2. Before water is introduced into the blast furnace body, compressed air is used to perform segmented leak checks on the completed cooling walls and connecting pipes. S3. Perform leak testing on the furnace bottom water cooling pipe system, including leak testing on the furnace bottom main water inlet pipe and the main and branch pipes of the recovery system, as follows: S3.

1. Inject industrial water from the blast furnace through the drain valve of the main return water pipe, gradually increase the water pressure to the normal production working pressure, check for leaks and seepage points and mark them, repair welding after draining the water, and inject water again to ensure there are no leaks. S3.2 After repairing the leaks and seepage points, continue to inject water to increase the pressure and maintain the pressure, confirming that there is no sweating or pressure drop; S4. Leak inspection of the main water supply pipe and loop system of the boiler body, as follows: S4.

1. Inject water from the drain valve of the water supply loop pipe of the furnace cooling wall, and close the drain valve of the loop pipe after water is seen coming out of the exhaust valve. S4.2 Gradually inject water to increase the pressure to the normal production working pressure, and continue to check for leaks until there are no leaks and no pressure drop. S4.3 Continue to inject water to increase pressure and continue to check for leaks until there are no leaks and no pressure drop. S5. Perform a comprehensive pressure test and leak check on the furnace water system, as follows: S5.

1. Fill the cooling wall with water from the inlet ring pipe and gradually increase the pressure. Close the vent valves of each platform pipe after water is seen. When the water pressure drops, check for leaks in each platform pipe and mark them. Deal with the leaks after depressurization. S5.2 After completing the leak repair, retest the pressure. If the pressure does not drop, the pressure test is qualified.

2. The method for pressure testing and leak detection of the blast furnace body water system as described in claim 1, characterized in that, In step S2, the steps for segmented leak detection are as follows: compressed air is introduced into the completed cooling wall, the outlet valve on the water pipe of each area and the inlet and outlet valves on the connecting pipe are closed, and the inlet and outlet valves on the cooling wall of the area to be leaked are opened, so that the water pipes and cooling wall water channels of the same number of the cooling wall to be leaked are connected.

3. The method for pressure testing and leak detection of the blast furnace body water system as described in claim 1, characterized in that, In step S2, the pressure of the compressed air is controlled at 80-90% of the cooling water pressure during normal production.

4. The method for pressure testing and leak detection of the blast furnace body water system as described in claim 1, characterized in that, In step S3.2, during the leak detection process, water is continuously injected to increase the pressure to 1.8-2.0 times the normal production working pressure, and the pressure holding time is ≥30 min.

5. The method for pressure testing and leak detection of the blast furnace water system as described in claim 1, characterized in that, In step S4.2, after water is injected to increase the pressure to the normal production working pressure, if the absence of leakage and pressure drop is maintained for ≥30 minutes, the leak detection and treatment are considered complete.

6. The method for pressure testing and leak detection of the blast furnace body water system as described in claim 1, characterized in that, In step S4.3, water is injected to increase the pressure to 1.8-2.0 times the normal production working pressure, and the pressure is maintained for ≥30 minutes without leakage or pressure drop, which is considered as passing the pressure test.

7. The method for pressure testing and leak detection of the blast furnace water system as described in claim 1, characterized in that, In step S5.1, the water pressure is increased to 1.2-1.4 times the normal production working pressure.

8. The method for pressure testing and leak detection of the blast furnace body water system as described in claim 1, characterized in that, In step S5.2, if there is no pressure drop after a holding time of ≥10 min during the re-pressure test, the pressure test is considered successful.