Auxiliary leakage detection method for soft water closed circulating cooling blast furnace
By analyzing the temperature data of the cooling wall of the blast furnace, calculating the temperature change rate, judging the leakage site, solving the problem of slow and low efficiency of the existing leakage method, and achieved faster and accurate water leakage detection.
Patent Information
- Application Number
- CN202411310319.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-19
- Publication Date
- 2025-01-28
AI Technical Summary
The existing blast furnace leak detection method is slow and inefficient. Frequently closing the valve of the cooling water pipe is likely to cause damage to the normal working water pipe, resulting in accelerated damage.
By analyzing the temperature data of the cooling wall, calculating the temperature change rate, finding the measured point with the maximum rate of temperature change, judging the possible water leakage parts, thereby reducing the amount of leakage work, and using key areas as the goal of leakage.
It greatly saves the time and labor of the leakage, reduces the damage to the normal working cooling wall water pipe, and improves the efficiency and accuracy of leakage.
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of blast furnace equipment maintenance methods, in particular to an auxiliary leak detection method for a blast furnace cooled by a closed soft water circulation. Background Art
[0002] The blast furnace cooling stave is a cooling device installed between the steel shell and the refractory lining of the blast furnace along the height of the blast furnace. It is equipped with water pipes and cooling water. Its function is to cool the refractory lining of the blast furnace and prevent the high heat flow in the furnace from causing deformation and cracking of the furnace shell.
[0003] Most blast furnaces now abandon the previous open-circuit cooling method of using industrial water in each cooling unit, and instead adopt a soft water closed-circuit cooling system that consumes less new water and is not prone to scaling. It is composed of cooling walls set at the same height of the blast furnace and distributed around the furnace body as a section, and the upper and lower sections are connected in series, and the cooling walls connected in series from bottom to top are a row. A blast furnace is usually composed of several cooling water pipes. In each section, each cooling wall usually contains 4-7 cooling water pipes, and the cooling water flows from bottom to top to cool the entire blast furnace. In a long-term high-temperature working environment, especially in the later stage of the furnace campaign, the cooling wall is severely damaged, and the leaking parts must be found out promptly and accurately and repaired in time.
[0004] The common leak detection methods are:
[0005] 1. When the liquid level in the expansion tank of the blast furnace soft water circulation cooling system drops too quickly and the water replenishment becomes abnormal, the water engineer closes the inlet and outlet valves of a certain column of water pipes one by one and observes the water pressure gauges at the inlet and outlet ends. When the water pressure is lower than the normal water pressure and close to the pressure inside the furnace, it can be preliminarily determined that the column of water pipes is damaged.
[0006] 2. Usually, the exhaust valve at the top of the closed section of the water pipe is opened, and when the water is drained and gas is emitted, it is ignited. When it catches fire, it can be determined that the row of water pipes is damaged.
[0007] 3. Check the confirmed damaged pipes section by section. Usually, close the inlet and outlet valves of the suspected cooling wall, open the exhaust valve on the cooling wall, and ignite it when the water is drained and gas is emitted. The fire and combustion can determine that the water pipe of the cooling wall is damaged.
[0008] 4. For cooling wall water pipes that are confirmed to be damaged, reduce the water pressure and switch to industrial water. If the leakage is confirmed to be large, it is usually sealed.
[0009] 5. Take advantage of the opportunity of blast furnace shutdown and maintenance to thread the damaged cooling wall water pipes or fill them with grout to completely block them or install a small cooler for maintenance.
[0010] The main disadvantages of this leak detection method are slow speed and low efficiency. In addition, the inlet and outlet valves of the cooling water pipe to be checked must be frequently closed during the leak detection process, which is equivalent to partially interrupting its cooling and easily damaging the normally working water pipe, thereby accelerating its damage. It usually takes about 2 hours from discovering the abnormal water replenishment to finding the specific leaking location, and multiple people collaborate. Summary of the invention
[0011] The technical problem to be solved by the present invention is that the main disadvantages of conventional leak detection methods are slow speed and low efficiency. In addition, during the leak detection process, the inlet and outlet water valves of the cooling water pipe to be checked must be frequently closed, which can easily damage the normally working water pipe and accelerate its breakage.
[0012] The main principle of the present invention is: under normal working conditions, before the cooling wall water pipe is damaged, it is usually washed by high-temperature coal gas flow, the cooling wall will bear a higher heat flux intensity, and the cooling wall temperature will usually rise at a higher speed and reach a higher value; and when the cooling wall is finally damaged and leaks, the cooling water will leak into the furnace from the damaged part, causing the cooling wall temperature near the leaking part to drop at a faster speed. Therefore, the possible leaking part can be roughly judged by the data change of the cooling wall temperature and after appropriate processing, thereby reducing the workload of leak detection.
[0013] To solve the above problems, the technical solution adopted by the present invention is as follows: The present invention is an auxiliary leak detection method for a soft water closed circulation cooling blast furnace, comprising the following steps:
[0014] Step 1: after an abnormality occurs in the water replenishment of the blast furnace soft water circulation cooling system, the cooling wall temperature data in a period of time before and after the abnormality occurs in the water replenishment in the blast furnace computer system is retrieved;
[0015] Step 2, screening the obtained cooling wall temperature data at each point;
[0016] Step 3, the cooling wall temperature data after filtering out the abnormal values is derived with respect to time, that is, the temperature change rate of each point in a period of time before and after the abnormal water replenishment occurs is calculated;
[0017] Step 4, find the maximum and minimum values of the cooling wall temperature change rate at each point in each section;
[0018] Step 5, find the measuring point with relatively large absolute value among the maximum and minimum values of the temperature change rate in each section of the cooling wall;
[0019] Step 6: Pay attention to finding the temperature measurement points in the upper and lower cooling walls where the absolute value of the temperature change rate is large and which are in similar positions in the circumferential direction;
[0020] Step 7: The middle part of each cooling wall section where the absolute value of the temperature change rate is large and is in the vertical direction can be judged as the possible area of cooling wall water pipe damage, and the corresponding cooling wall water pipe number and cooling wall section that need to be checked in detail can be determined accordingly;
[0021] Step eight, take this area as the key inspection area for cooling wall water pipe leakage, and then use conventional leak detection methods to check for leaks.
[0022] Furthermore, the temperature measuring tool in step 1 uses existing temperature measuring instruments of blast furnaces such as thermocouples installed on the cooling wall.
[0023] Furthermore, in step 1, more than five groups of temperature data need to be measured.
[0024] Furthermore, the temperature data screening in step 2 is to remove abnormal data caused by thermocouple damage and maintenance.
[0025] The beneficial effects achieved by the present invention using the above structure are as follows:
[0026] When an abnormality occurs in the water replenishment of the blast furnace soft water closed circulation cooling system, the possible damaged parts can be quickly identified, so that highly targeted leak detection can be carried out, which greatly saves the time and labor required for leak detection and greatly reduces the damage caused by leak detection to the normally working cooling wall water pipes. DETAILED DESCRIPTION
[0027] The present invention is an auxiliary leak detection method for a soft water closed circulation cooling blast furnace, comprising the following steps:
[0028] Step 1: After the water replenishment of the blast furnace soft water circulation cooling system is abnormal, the cooling wall temperature data of the blast furnace computer system before and after the abnormal water replenishment is retrieved. The temperature measuring tool uses the existing temperature measuring instrument of the blast furnace such as the thermocouple installed on the cooling wall body. More than five groups of temperature data need to be measured;
[0029] Step 2: Screen the obtained cooling wall temperature data at each point to remove abnormal data caused by thermocouple damage and maintenance;
[0030] Step 3, the cooling wall temperature data after filtering out the abnormal values is derived with respect to time, that is, the temperature change rate of each point in a period of time before and after the abnormal water replenishment occurs is calculated;
[0031] Step 4, find the maximum and minimum values of the cooling wall temperature change rate at each point in each section;
[0032] Step 5, find the measuring point with relatively large absolute value among the maximum and minimum values of the temperature change rate in each section of the cooling wall;
[0033] Step 6: Pay attention to finding the temperature measurement points in the upper and lower cooling walls where the absolute value of the temperature change rate is large and which are in similar positions in the circumferential direction;
[0034] Step 7: The middle part of each cooling wall section where the absolute value of the temperature change rate is large and is in the vertical direction can be judged as the possible area of cooling wall water pipe damage, and the corresponding cooling wall water pipe number and cooling wall section that need to be checked in detail can be determined accordingly;
[0035] Step eight, take this area as the key inspection area for cooling wall water pipe leakage, and then use conventional leak detection methods to check for leaks.
[0036] Example:
[0037] A factory with 2800m2 of soft water closed circulation cooling 3 The blast furnace is equipped with 16 cooling walls from the hearth to the top of the furnace body, with a total of 196 cooling water pipes. Among them, the 2nd and 3rd cooling walls of the hearth are each equipped with 8 temperature measuring thermocouples in the circumferential direction, the 6th to 9th copper cooling walls are equipped with 8 temperature measuring thermocouples in the circumferential direction, and 4 thermocouples are installed on the cold surface, with a total of 12 temperature measuring thermocouples in each section, the 10th to 12th cast iron cooling walls are each equipped with 13 temperature measuring thermocouples in the circumferential direction, and the 13th to 16th sections are each equipped with 8 temperature measuring thermocouples in the circumferential direction. The water supply method adopts a bottom-up series connection method. At around 6 o'clock in the morning on January 10, 2023, the liquid level in the expansion tank of the cooling water system of the blast furnace cooling wall decreased, indicating that there was a leak in the cooling water system. Take this example to illustrate the leak detection method of the present invention:
[0038] Step 1: retrieve the hourly cooling wall temperature data for a period of time before and after the abnormal water replenishment, for example, the 24 hours before 10:00 on January 10, in the secondary computer system of the blast furnace;
[0039] Step 2: Screen the obtained cooling wall temperature data at each point, and find out that the thermocouple at the 11th temperature measuring point at the 7th section (elevation 19.450M) of the blast furnace is damaged and the data is abnormal, so the abnormal data at this point is removed;
[0040] Step 3: Use a spreadsheet to calculate the temperature change rate of the cooling wall temperature data after filtering out abnormal values, that is, subtract the average temperature value of the previous hour from the average temperature value of the current hour to calculate the temperature change rate of each measuring point before and after the abnormal water replenishment occurs;
[0041] Step 4, respectively find out the maximum and minimum values of the cooling wall temperature change rate at each point in each section of the cooling wall, and obtain a data table as shown in Table 1;
[0042] Step 5, focus on finding the measuring points with relatively large absolute values of the temperature change rate in each section of the cooling wall. From Table 1, it can be seen that the absolute values of the maximum and minimum values of the temperature change rate of the cooling wall in sections 2, 3 and above 11 are not very large, while the absolute values of the temperature change rate in sections 6-10 are relatively large.
[0043] Step 6: Pay attention to finding the temperature measuring points with large absolute values of temperature change rate in the upper and lower cooling walls and in similar positions in the circumferential direction. From Table 1, it can be seen that in this water leakage incident, the absolute values of the temperature change rate of measuring points 3 and 4 in the 7th section, measuring points 4 and 5 in the 8th section, measuring point 5 in the 9th cooling wall, and measuring points 7, 8, and 9 in the 10th cooling wall (because there are 13 measuring points in the circumferential direction of this section, and there are only 8 measuring points in the circumferential direction of sections 6-9, measuring points 9-12 are arranged on the cold surface, so they are roughly the same as the positions of measuring points 4 and 5 in the 7th to 9th cooling walls in the circumferential direction of the blast furnace) are relatively large;
[0044] Step 7: Based on this, the cooling wall water pipe in the middle of the area, that is, between the 4th and 5th measuring points of the 8th and 9th cooling wall, can be judged as the cooling wall water pipe that is most likely to be damaged, that is, the water pipe corresponding to the pipe number between pipes 130 and 156, and the damaged section can be preliminarily judged to be the middle section of sections 7-10, that is, section 8 or section 9, thereby preliminarily determining the approximate area of the damaged cooling wall water pipe;
[0045] Step eight, this area was taken as the key area for checking cooling wall water pipe leakage, and the conventional leak detection method mentioned above was used to check for leaks. It was finally determined that the ninth section of pipe No. 149 was damaged.
[0046] Table 1 Maximum and minimum values of the temperature change rate of the cooling wall at each point on each section of a blast furnace
[0047]
[0048] It should be understood that although this specification is described according to implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.
Claims
1. An auxiliary leak detection method for a soft water closed cycle cooling blast furnace, characterized in that: The steps include: Step 1: after an abnormality occurs in the water replenishment of the blast furnace soft water circulation cooling system, the cooling wall temperature data in a period of time before and after the abnormality occurs in the water replenishment in the blast furnace computer system is retrieved; Step 2, screening the obtained cooling wall temperature data at each point; Step 3, the cooling wall temperature data after filtering out the abnormal values is derived with respect to time, that is, the temperature change rate of each point in a period of time before and after the abnormal water replenishment occurs is calculated; Step 4, find the maximum and minimum values of the cooling wall temperature change rate at each point in each section; Step 5, find the measuring point with relatively large absolute value among the maximum and minimum values of the temperature change rate in each section of the cooling wall; Step 6: Pay attention to finding the temperature measurement points in the upper and lower cooling walls where the absolute value of the temperature change rate is large and which are in similar positions in the circumferential direction; Step 7: The middle part of each cooling wall section where the absolute value of the temperature change rate is large and is in the vertical direction can be judged as the possible area of cooling wall water pipe damage, and the corresponding cooling wall water pipe number and cooling wall section that need to be checked in detail can be determined accordingly; Step eight, take this area as the key inspection area for cooling wall water pipe leakage, and then use conventional leak detection methods to check for leaks.
2. The auxiliary leak detection method for a soft water closed cycle cooling blast furnace according to claim 1, characterized in that: The temperature measuring tool in step 1 uses an existing temperature measuring instrument for a blast furnace, such as a thermocouple installed on a cooling wall.
3. The auxiliary leak detection method for a soft water closed cycle cooling blast furnace according to claim 1, characterized in that: In step 1, more than five sets of temperature data need to be measured.
4. The auxiliary leak detection method for a soft water closed cycle cooling blast furnace according to claim 1, characterized in that: The temperature data screening in step 2 is to remove abnormal data caused by thermocouple damage and maintenance.