A method for online detection of radiation tubes in cold rolling annealing furnace

Abstract

The present invention discloses an online detection method for radiant tubes of a cold rolling annealing furnace, which specifically includes the following steps: 1) installing a NO gas detector on the top of the middle section of the heating section of the radiant tube of the annealing furnace; 2) controlling the hydrogen content in the furnace to be greater than 3%, and controlling the temperature of the radiant tube in the furnace to be greater than 600°C, so that the radiant tube is in a working state; 3) detecting the NO gas content in the furnace when the furnace top relief valve is in a closed state; 4) detecting the radiant tube layer by layer from the top to the bottom; 5) detecting all the radiant tubes one by one in the layer area where leakage exists. The online detection method for radiant tubes of a cold rolling annealing furnace of the present invention can effectively and conveniently and quickly detect the radiant tubes in the annealing furnace online, quickly find out the damaged radiant tubes, improve the maintenance efficiency, avoid safety hazards, and optimize the product quality.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgy, and in particular relates to an online detection method for radiation tubes of a cold rolling annealing furnace. Background Art

[0002] In metallurgical technology, most cold rolling annealing furnaces use radiant tubes for heating to achieve annealing. Radiant tubes usually use coal gas or natural gas as fuel. Under normal conditions, the exhaust gas after combustion is discharged into the atmosphere through the exhaust gas pipeline. During the production process, the radiant tubes inevitably have phenomena such as burn-through and cracking. Part of the exhaust gas will enter the annealing furnace through the damaged radiant tubes (the exhaust gas composition contains NO gas), causing defects such as stains, oxidation and plating leakage on the strip. Therefore, it is necessary to find and deal with the damaged radiant tubes. The traditional search method is through appearance inspection, which affects normal production; another method is to shut down the radiant tubes one by one for search under normal production conditions. Due to the large number of radiant tubes in the annealing furnace, it takes a long time to search one by one, which is inefficient and difficult to meet the needs of modern production.

[0003] The Chinese patent specification discloses an online leak detection method and device for heat treatment furnace radiant tubes (publication number CN102853976B), and specifically discloses the following contents: seal the heat treatment furnace radiant tubes; detect the gas flow at any interface of the heat treatment furnace radiant tubes; if the gas flow is greater than zero, the heat treatment furnace radiant tubes have a leak, and if the gas flow is zero, the heat treatment furnace radiant tubes are normal and have no leaks. Although the method and device achieve the purpose of online detection, the method used is to detect the radiant tube monomers one by one, and its detection efficiency is still not optimistic.

[0004] The Chinese patent specification also discloses an online search method for damaged radiant tubes in an annealing furnace (publication number CN110967147B), and specifically discloses the following contents: including detecting the opening of the pressure control damper; detecting the amount of nitrogen injection; observing the temperature value of the exhaust gas after combustion in each section of the annealing furnace; detecting the oxygen content value of the exhaust gas in the radiant tube; and determining the damage of the radiant tube based on the oxygen content value. This method can identify damaged radiant tubes online without stopping the machine and the annealing furnace is heated, but during the execution of this method, it is necessary to measure the exhaust gas temperature, sample the exhaust gas, and analyze the flue gas, and the process is still relatively cumbersome. Summary of the invention

[0005] 1. Technical issues to be solved

[0006] The invention provides an online detection method for radiant tubes in a cold rolling annealing furnace, the purpose of which is to conveniently and quickly perform online detection on radiant tubes in the annealing furnace and quickly find out damaged radiant tubes.

[0007] 2. Technical Solution

[0008] The present invention adopts the following technical scheme, and finds the radiation tube that has leakage by detecting the change of NO gas content in the exhaust gas components in the annealing furnace, which specifically includes the following steps:

[0009] 1) Install a NO gas detector on the top of the middle section of the annealing furnace radiation tube heating section;

[0010] 2) The hydrogen content in the furnace is controlled to be greater than 3%, and the temperature of the radiation tube in the furnace is controlled to be greater than 600°C, so that the radiation tube is in working condition;

[0011] 3) When the furnace top vent valve is in the closed state, detect the NO gas content in the furnace. If it is less than 20ppm, proceed to step 6); if it is greater than 40ppm, proceed to step 4);

[0012] 4) Inspect the radiation tubes layer by layer from top to bottom;

[0013] 4.1 Turn off all radiation tubes in a single layer area,

[0014] 4.2 Open the furnace top relief valve and close it after 5 minutes.

[0015] 4.3 Detect the NO gas content in the furnace. If it is less than 20ppm, determine that there is a leaking radiation tube in the radiation tube of the layer area and go to step 5). If it is greater than 40ppm, turn on all the radiation tubes in the layer area and repeat step 4).

[0016] 5) For the layer area with leakage, all the radiation tubes are tested one by one;

[0017] 5.1 Turn on a single radiant tube,

[0018] 5.2 Detect the NO gas content in the furnace. If it is less than 20ppm, repeat step 5). If it is greater than 20ppm, the opened radiation tube is a leaking radiation tube. Close the leaking radiation tube and repeat step 5).

[0019] 6) The test is completed.

[0020] The radiation tube is closed to stop the radiation tube from burning; the radiation tube is opened to put the radiation tube into burning state.

[0021] The NO gas detector is an infrared gas detector.

[0022] 3. Beneficial Effects

[0023] The invention discloses an online detection method for radiant tubes in a cold rolling annealing furnace, which can effectively and conveniently and quickly perform online detection on radiant tubes in the annealing furnace, quickly find out damaged radiant tubes, improve maintenance efficiency, avoid potential safety hazards, and optimize product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention is a flow chart of the online detection method of the radiation tube of the cold rolling annealing furnace.

[0025] Figure 2 It is a schematic diagram of the arrangement of radiation tubes of the annealing furnace of the present invention. DETAILED DESCRIPTION

[0026] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings to facilitate a clearer understanding for those skilled in the art.

[0027] Example

[0028] like Figure 2 As shown, in this embodiment, six layers of radiation tubes are arranged in the annealing furnace from top to bottom, namely: first layer 1, second layer 2, third layer 3, fourth layer 4, fifth layer 5, and sixth layer 6.

[0029] like Figure 1 , Figure 2 As shown, this embodiment specifically includes the following steps:

[0030] 1) Install a NO gas detector 7 on the top of the middle section of the annealing furnace radiation tube heating section;

[0031] 2) The hydrogen content in the furnace is controlled to be greater than 3%, and the temperature of the radiation tube in the furnace is controlled to be greater than 600°C, so that the radiation tube is in working condition;

[0032] 3) When the furnace top vent valve is in the closed state, detect the NO gas content in the furnace. If it is less than 20ppm, the entire detection is completed. If it is greater than 40ppm, proceed to step 4);

[0033] 4) Inspect the radiation tube layer by layer from top to bottom;

[0034] Inspection side of the first layer

[0035] Close all radiation tubes in zone 1 of the first layer, open the furnace top vent valve for 5 minutes and then close it, and detect the NO gas content in the furnace, which can be divided into two situations:

[0036] If it is less than 20ppm, it is determined that there is a leaking radiation tube in the radiation tubes of the first layer. All the radiation tubes in the first layer are tested one by one. A single radiation tube is opened to detect the NO gas content in the furnace. If it is less than 20ppm, a single radiation tube is opened in sequence. If it is greater than 20ppm, the opened radiation tube is a leaking radiation tube. The leaking radiation tube is closed and a single radiation tube is opened in sequence until all the radiation tubes in the first layer are tested. This ends the entire test.

[0037] If >40ppm, all radiation tubes in the first layer area 1 are turned on and the second layer area is tested.

[0038] Inspection of the second layer

[0039] Close all radiation tubes in zone 2 of the second layer, open the furnace top vent valve for 5 minutes and then close it, and detect the NO gas content in the furnace, which can be divided into two situations:

[0040] If it is less than 20ppm, it is determined that there is a leaking radiation tube in the radiation tubes of the second layer. All the radiation tubes in the second layer are tested one by one. A single radiation tube is opened to detect the NO gas content in the furnace. If it is less than 20ppm, a single radiation tube is opened in sequence. If it is greater than 20ppm, the opened radiation tube is a leaking radiation tube. The leaking radiation tube is closed and a single radiation tube is opened in sequence until all the radiation tubes in the second layer are tested. This ends the entire test.

[0041] If >40ppm, all radiation tubes in the second layer 2 are turned on and the third layer is tested.

[0042] Detection of the third layer area

[0043] Close all radiation tubes in zone 3 of the third layer, open the furnace top vent valve for 5 minutes and then close it, and detect the NO gas content in the furnace, which can be divided into two situations:

[0044] If it is less than 20ppm, it is determined that there is a leaking radiation tube in the radiation tubes of the third layer area, and all the radiation tubes in the third layer area are tested one by one. Open a single radiation tube and test the NO gas content in the furnace. If it is less than 20ppm, continue to open the single radiation tube in sequence. If it is greater than 20ppm, the opened radiation tube is a leaking radiation tube. Close the leaking radiation tube and continue to open the single radiation tube in sequence until all the radiation tubes in the third layer area are tested, that is, the entire test is completed.

[0045] If >40ppm, all radiation tubes in the third layer 3 are turned on and the fourth layer is tested.

[0046] Detection of the fourth layer area

[0047] Close all radiation tubes in zone 4 on the fourth floor, open the furnace top vent valve for 5 minutes and then close it, and detect the NO gas content in the furnace, which can be divided into two situations:

[0048] If it is less than 20ppm, it is determined that there is a leaking radiation tube in the radiation tubes in the fourth layer area, and all the radiation tubes in the fourth layer area are tested one by one. Open a single radiation tube and test the NO gas content in the furnace. If it is less than 20ppm, continue to open the single radiation tube in sequence. If it is greater than 20ppm, the opened radiation tube is a leaking radiation tube. Close the leaking radiation tube and continue to open the single radiation tube in sequence until all the radiation tubes in the fourth layer area are tested, that is, the entire test is completed.

[0049] If >40ppm, all radiation tubes in the fourth layer 4 are turned on and the fifth layer is tested.

[0050] Detection of the fifth layer area

[0051] Close all radiation tubes in zone 5 of the fifth layer, open the furnace top vent valve for 5 minutes and then close it, and detect the NO gas content in the furnace, which can be divided into two situations:

[0052] If it is less than 20ppm, it is determined that there is a leaking radiation tube in the radiation tubes in the fifth layer. All the radiation tubes in the fifth layer are tested one by one. Open a single radiation tube and test the NO gas content in the furnace. If it is less than 20ppm, continue to open the single radiation tube in sequence. If it is greater than 20ppm, the opened radiation tube is a leaking radiation tube. Close the leaking radiation tube and continue to open the single radiation tube in sequence until all the radiation tubes in the fifth layer are tested. This ends the entire test.

[0053] If >40ppm, all radiation tubes in the fifth layer 5 are turned on and the sixth layer is tested.

[0054] Detection of the sixth layer area

[0055] Close all radiation tubes in the sixth layer area 6, open the furnace top vent valve for 5 minutes and then close it, and detect the NO gas content in the furnace. At this time, there will be only one situation, namely: <20ppm, which determines that there is a leaking radiation tube in the radiation tubes in the sixth layer area. All radiation tubes in the sixth layer area are tested one by one, and a single radiation tube is opened to detect the NO gas content in the furnace. If it is <20ppm, continue to open the single radiation tube in sequence. If it is >20ppm, the opened radiation tube is a leaking radiation tube. Close the leaking radiation tube and continue to open the single radiation tube in sequence until all the radiation tubes in the sixth layer are inspected, that is, the entire detection is completed.

[0056] The radiation tube is closed to stop the radiation tube from burning; the radiation tube is opened to put the radiation tube into burning state.

[0057] The NO gas detector is an infrared gas detector.

[0058] The present invention first detects the layer area and then detects the single radiation tube in the layer area, which quickly narrows the search range and greatly improves the efficiency of finding the damaged radiation tube. The operation process is convenient and very suitable for wide application in actual production.

[0059] The invention discloses an online detection method for radiant tubes in a cold rolling annealing furnace, which can effectively and conveniently and quickly perform online detection on radiant tubes in the annealing furnace, quickly find out damaged radiant tubes, improve maintenance efficiency, avoid potential safety hazards, and optimize product quality.

[0060] The present invention is not limited to the above-mentioned specific implementation modes, and various improvements made by those skilled in the art to the technical solutions according to the concept of the present invention shall all fall within the scope of protection claimed by the present invention.

Claims

1. A method for online detection of radiant tubes in a cold rolling annealing furnace, characterized in that: By detecting the change of NO gas content in the exhaust gas composition in the annealing furnace, the leaking radiation tube is found, which specifically includes the following steps: 1) Install a NO gas detector on the top of the middle section of the annealing furnace radiation tube heating section; 2) Control the hydrogen content in the furnace to be greater than 3% and the temperature of the radiation tube in the furnace to be greater than 600 o C. Keep the radiation tube in working condition; 3) When the furnace top vent valve is in the closed state, detect the NO gas content in the furnace. If it is less than 20ppm, proceed to step 6); if it is greater than 40ppm, proceed to step 4); 4) Inspect the radiation tubes layer by layer from top to bottom; 4.1 Turn off all radiation tubes in a single layer area, 4.2 Open the furnace top relief valve and close it after 5 minutes. 4.3 Detect the NO gas content in the furnace. If it is less than 20ppm, determine that there is a leak in the radiation tubes in the layer area and go to step 5). If it is greater than 40ppm, turn on all the radiation tubes in the layer area and repeat step 4). 5) For the layer area with leakage, all the radiation tubes are tested one by one; 5.1 Turn on a single radiant tube, 5.2 Detect the NO gas content in the furnace. If it is less than 20ppm, repeat step 5). If it is greater than 20ppm, the opened radiation tube is a leaking radiation tube. Close the leaking radiation tube and repeat step 5). 6) The test is completed.

2. The method for online detection of radiant tubes of cold rolling annealing furnace according to claim 1, characterized in that: Closing the radiation tube stops the radiation tube from burning; opening the radiation tube puts the radiation tube into a burning state.

3. The online detection method for radiant tubes of cold rolling annealing furnace according to claim 1 or 2, characterized in that: The NO gas detector is an infrared gas detector.

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