JPH01149909A - Method for detecting leakage of cooling piping for furnace bottom in blast furnace - Google Patents

Abstract

PURPOSE:To easily detect leakage of cooling water in cooling piping group for furnace bottom by closing end part at drainage side of the cooling piping for the furnace bottom and the other end part of the piping after pressurizing the inner part in the piping with the cooling water and executing the operation for detecting pressure dropping in the piping in order all over the pipings. CONSTITUTION:A shutt-off valve 5 at the drainage side in at least one piece of piping 2 in the cooling piping 2 group for the furnace bottom in a blast furnace is closed and the inner part in this piping 2 is pressurized with the cooling water and successively, a shut-off valve 4 at the water supplying side in the piping 2 is closed. By this method, the pressure of cooling water between both cut-off valves 4, 5 is measured with a pressure gage 6 and recorded in a recorder 7. This operation is executed in order to over the whole pipings 2 and the leakage of the cooling water in the piping 2 is detected from the pressure drop in the piping 2. By this method, the piping 2 which the cooling water leaks therethrough, is easily detected.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides a leakage detection method for blast furnace bottom cooling piping that can easily detect leakage in blast furnace bottom cooling piping during blast furnace operation or blow-off. It is related to.

<Prior Art> Blast furnace bottom cooling piping has an important role of cooling furnace bottom bricks and suppressing brick erosion. Therefore, crack damage to the cooling piping is being investigated after blowdown during blast furnace renovation.

The above investigation was conducted by scraping out all of the hearth bricks, peeling off the bottom plate of the hearth, exposing the piping, and then visually checking for cracks and damage.

However, with this method, even if you want to continue using some of the hearth bricks or the hearth bottom plate, the bricks and bottom plate are dismantled as described above, regardless of whether or not there is crack damage to the hearth cooling piping.
Since the piping is inspected, if the bottom cooling piping is healthy, this disassembly will be a waste of work. Furthermore, even if a small number of pipes are damaged by cracks, all the bottom plates must be peeled off, resulting in unnecessary dismantling and hindering shortening of the repair period.

In addition to the above-mentioned technology, there is a pipeline leak detection device disclosed in Japanese Patent Application Laid-Open No. 49-2115, but in a large blast furnace, the number of pipes is 40 to 60 and the length is about 30 m.
When the above device is used, the device must be put in and taken out manually, and the cooling water must be stopped and passed through the piping group manually, and the area around the bottom of the furnace must be manually removed. The work is extremely difficult in a hostile environment, and the measurement takes a long time. Furthermore, in order to measure a plurality of pipes at the same time, a plurality of measuring devices are required, which increases the cost and is not suitable for detecting crack damage in blast furnace bottom cooling pipes.

<Problems to be Solved by the Invention> As mentioned above, the conventional methods have various problems, and the present invention solves these problems and prevents leakage from the blast furnace bottom cooling piping even during blast furnace operation. This was done in order to provide a method for managing blast furnace bottom cooling piping that can be automatically detected without using complicated and expensive equipment.

<Means for Solving the Problems> As a result of intensive research into a simple and reliable leak detection method for blast furnace bottom cooling piping, the inventors of the present invention have discovered that by blocking both ends of each piping, the pressure inside the piping can be detected. We have learned that leakage in pipes can be detected from the drop, and based on this knowledge, we have developed the present invention.

The present invention provides a method for pressurizing the inside of the pipe with cooling water while the drain side end of at least one pipe of the blast furnace bottom cooling pipe group is closed, and then the other end of the pipe is also closed. This is a method for detecting leakage in blast furnace bottom cooling piping, in which piping leakage is detected sequentially over all piping based on the pressure drop in the piping after the supply of cooling water is stopped.

<For production> The present invention will be explained below with reference to FIGS. 1 and 2.

The bottom cooling pipe 2 has one end on the water supply side connected to the header 1 and the other end on the drainage side open, and is connected to the bottom plate 1 of the blast furnace main body 8.
It is buried under the bottom surface of 0. Further, the cooling water flowing through the pipe is drained from the drain pipe 3 to the drain pit 9. In order to maintain the pressure inside the pipe 2, a shutoff valve 4.5 is provided on the water supply side and the drain side of the pipe 2, and a pressure gauge 6 is provided to detect the pressure inside the pipe, and a pressure gauge 6 is provided to record the pressure. A recorder 7 is provided.

Leakage in the bottom cooling piping is detected using the device described above in the following manner.

Close the drain side shutoff valve 5 of at least one pipe of the 2 groups of furnace bottom cooling pipes, and then close the water supply side shutoff valve 4 for a short time.
Let be closed. The pressure between the re-shutoff valves is measured with the meter 6, and the leakage of the piping is detected from the pressure drop situation. The operation of 0 or more is sequentially scanned and repeated for each piping using a timer. Next, FIG. 3 shows an aspect of scanning. Further, after the detection is completed, the water supply side shutoff valve 4 of the piping is opened, and after a short period of time, for example, about 30 seconds, the drainage side shutoff valve 5 is opened, and water starts flowing sequentially.

<Example> In a blast furnace with a production capacity of 10,000 t/d and equipped with 40 bottom cooling pipes (length: approximately 30 m/piece), the presence or absence of leakage in the bottom cooling pipes was determined using the method of the present invention. Detection work was carried out during blast furnace operation.

The water flow pressure was 2 kg/cd, and the time required for measurement was approximately 6 minutes per bottom cooling pipe, and approximately 3.5 hours for this blast furnace, which had 40 pipes in total. Compared to the detection method, which took about 79 hours, the presence or absence of a leak could be detected during height operation in a much shorter time.

An example is shown in FIG. 3, with cooling pipes A and B.

In case C, there was no pressure drop inside the piping and no leakage was detected in the piping, but in the case of cooling piping, there was a pressure drop in the piping and crack damage in the piping was detected. Leakage of the piping was temporarily prevented by injecting mortar, etc., and during the next blast furnace renovation, only the bottom bricks and bottom plates around the piping were dismantled, allowing repairs to be carried out in a short time.

<Effects of the Invention> According to the present invention, leakage of the bottom cooling pipe can be detected even during blast furnace operation, and the scope of disassembly and repair during the next repair can be minimized.

Furthermore, the bottom cooling piping can be managed at low cost without requiring a complicated and expensive detection device.

[Brief explanation of the drawing]

FIG. 1 is a front cross-sectional view of the bottom of a blast furnace for explaining the present invention, FIG. 2 is a cross-sectional view taken along the line A-A in FIG. 1, and FIG. be. 1... Header, 2... Hearth cooling piping, 3
...Drain pipe, 4...Shutoff valve, 5...Shutoff valve, 6...Pressure gauge, 7...Recorder,
8... Blast furnace main body, 9... Drainage pit,
10... Hearth bottom plate, 11... Hearth bottom concrete. Patent applicant: Kawasaki Steel Corporation Figure 1 Figure 2

Claims (1)

[Claims] With the drainage side end of at least one pipe in the group of blast furnace bottom cooling pipes closed, the inside of the pipe is pressurized with cooling water, and then the other end of the pipe is also closed to supply cooling water. 1. A method for detecting leakage in blast furnace bottom cooling piping, characterized by sequentially detecting leakage in piping from the state of pressure drop in the piping after stopping the blast furnace.