CN103031396A - Method for leakage detecting and handling of blast furnace soft water closed circulating cooling system - Google Patents

Abstract

The invention provides a leak detection and disposal method for the blast furnace soft water closed circulation cooling system. Through the change of the liquid level difference of the expansion tank of the soft water system, the pressure trend of the gas is detected in the expansion tank or the degassing tank, and the closed circulation cooling system cools down. The water flow in the flap flow meter on the wall has bubbles or cloudiness, and the pH value continues to decrease slowly. The judgment of the water marks on the eye plate of the blast furnace skin and the seepage of Glauber's salt indicates the damage of the cooling wall or the inner wall of the pipeline. ; Then use the flap flowmeter to determine the damaged point of the cooling wall water pipe, and implement longitudinal disposal; use the method of installing a pressure gauge to pressurize the leak detection method to determine the damaged point of the cooling water pipe, and implement horizontal disposal. The method improves work efficiency, reduces labor intensity, detects leaks and handles leaks in time, and provides a solid foundation for safe, smooth and stable production of the blast furnace.

Description

A Leak Detection and Disposal Method for Blast Furnace Soft Water Closed Circulation Cooling System

technical field

The invention relates to the leak detection test and disposal of the soft water closed cycle cooling system of the blast furnace. The method is simple, fast and accurate, and has important practical and popularization value.

Background technique

After the cooling system (cooling wall, large and middle casing) in the soft water closed circulation cooling system of the blast furnace is damaged, it is usually used to check the leak by pressing the pressure gauge or lighting the gas fire to determine whether the cooling wall in the cooling water pipeline is damaged. However, due to the large number of staves, large and middle sets, there are about 700 staves, which are divided into 16 layers. 10. There are 43 cooling water pipes in the back pipe of the stave on the 11th floor, and there are a total of 283 cooling water pipes that need to be suppressed; under normal production conditions, use the pressure gauge to suppress the leak detection method or the gas fire method to detect leaks, and at least 4 people are required to watch the water It takes about 10 minutes to press and leak each cooling water pipe at the same time. Every time the cooling wall of the furnace soft water system is pressed (longitudinal) for leak detection, all the cooling water pipes need to be pressed one by one. Check for leaks twice to confirm that all leaking cooling water pipes have been checked out, so it takes at least about 5660 minutes to complete; the above two methods for leak checking are labor-intensive, labor-intensive, and time-consuming. Leakage points lead to vicious accidents such as freezing of the water inlet hearth in the furnace; in addition, the gas concentration in the furnace body of the blast furnace is about 500ppm, and there is a great potential safety hazard when personnel detect leaks; Leakage technology requires 566 times of drainage, and a large amount of soft water is discharged, which affects the energy-saving and consumption-reducing indicators of the enterprise.

Advantages of the technical characteristics of the present invention: 1) It takes about 5 minutes to accurately determine the internal leakage of the cooling wall of the soft water closed circulation cooling system of ^three large blast furnaces with an area of 2500m3. According to the method, the working time needs at least about 5660 minutes, which is shortened by more than 5650 minutes, which greatly improves the work efficiency and reduces the labor intensity. 2) Put an end to long-term work in the gas area by looking at the waterworks to ensure safe production; the blast furnace stave leak inspection site is on the 36.5-meter platform of the furnace body, and there is a great potential safety hazard when personnel leak inspection. 3) Find out the leakage point of the stave in time to avoid excessive water inflow into the furnace, resulting in vicious accidents such as furnace cooling and hearth freezing. 4) Eliminate the discharge of a large amount of soft water. The original leak detection technology requires 566 times of drainage, resulting in waste. This method is used to reduce the cost of ironmaking.

Contents of the invention

The purpose of the present invention is to provide a leak detection and treatment method that greatly improves work efficiency, reduces labor intensity, detects leaks and treats leaks in time, and provides a solid foundation for safe, smooth and stable production of the blast furnace.

The object of the present invention is achieved in that a kind of leak detection and disposal method for the soft water closed circulation cooling system of blast furnace is divided into the disposal measures of leak detection and leak repair:

Step 1 Leak detection judgment:

1) The normal range of the liquid level of the expansion tank of the soft water system is 3.1-3.4 meters. When it is lower than 3.1 meters, frequent replenishment of water is required, indicating that the water in the cooling wall leaks into the furnace, and the cooling wall of the blast furnace is damaged;

2) Coal gas is detected in the expansion tank or degassing tank of the soft water system, indicating that the pressure of soft water on the upper part of the furnace body is lower than the gas pressure in the furnace on the upper part of the furnace body, and the gas in the furnace is reversed, that is, the gas enters through the damaged cooling wall In the soft water system, the cooling wall is damaged; at this time, the circulating pressure in the upper cooling wall of the furnace body is 0.20-0.22mPa, and the gas pressure at the upper part of the furnace body is 0.23-0.24mPa;

3) The cooling wall of the soft water closed circulation cooling system has 16 layers in the vertical direction, and 45 cooling walls are installed in each layer in the horizontal direction. There are 4 cooling water pipes in each cooling wall, and there are 180 cooling water pipes in total; 180 flap flowmeters are used for real-time monitoring. The water flow in the flap flowmeter has air bubbles or is cloudy, indicating that the cooling wall including the cooling water pipeline in the longitudinal direction of the cooling wall is damaged;

4) The normal pH value of the soft water quality test is 8-10. When the pH value continues to decrease slowly from 9.2↘8.9↘8.1↘7.5, it is determined that the gas in the furnace has entered the soft water system, and the carbon dioxide in the gas dissolves into the water to form carbonic acid. Weak acidity, resulting in a decrease in pH value, indicating that the cooling wall is damaged;

5) Observe that there are water marks and seepage of Glauber's salt on the eye plate of the blast furnace skin, that is, it is confirmed that the water entering the furnace is carried out by the gas, entraining the grouting material in the furnace skin, that is, water seeps out at the gas leakage point of the furnace skin , Glauber's salt, indicating that the cooling wall is damaged;

Step 1 Leak detection treatment:

Longitudinal disposal: Observe the flap flowmeter on each stave outlet cooling water pipe on the 16th floor stave, and determine the position of the stave water pipe is damaged, that is, carry out disposal;

Horizontal treatment: 1. Use the method of installing pressure gauges to pressurize and detect leaks, that is, close the three-way valve layer by layer. Which layer of cooling wall has pressure relief phenomenon, which indicates that the cooling water pipe of which layer of cooling wall is damaged; 2. Close the root The cooling water pipe enters and exits the water valve, and observes the water level in the cooling water pipe leaks to which layer it stops falling, which indicates that the cooling water pipe of the stave wall on which layer is damaged; that is, carry out disposal.

The method is suitable for leak detection in a large blast furnace with a flap flowmeter on a soft water return pipeline.

The invention observes the change of the liquid level of the expansion tank of the soft water system, detects the gas concentration in the degassing tank of the soft water system, observes the water flow state in the flap flowmeter on the return water pipeline of the soft water, and analyzes the change trend of the pH value of the water quality to observe the blast furnace Whether there are water traces, Glauber’s salt and other exudates on the eye plate of the furnace skin, so as to judge whether the cooling wall of the soft water closed circulation cooling system of the blast furnace is damaged; and then use the leak detection method of the flap flowmeter, and use the method of layer-by-layer inspection by installing leak detection valves. Finally determine which layer of the cooling water pipe is leaking (horizontal), so as to determine the specific layer (horizontal) and which (vertical) stave leaking, so as to deal with it quickly, avoid affecting the normal production of the blast furnace, and demonstrate technological progress .

the

Detailed ways

The present invention will be further described in conjunction with embodiment

Example

Leak detection steps:

1) During normal production, the liquid level of the expansion tank of the soft water system is maintained at 3.1 meters, which is relatively stable. Unless the water pump room cleans the soft water self-cleaner, the liquid level of the expansion tank of the soft water system will fluctuate up and down. If the expansion tank of the soft water system is found The liquid level cannot be stabilized and continues to drop. For example, the liquid level changes from 3.4m↘3.2m↘3.1m↘3.0m..., indicating that the water in the cooling wall of the soft water system leaks into the furnace, and the cooling wall of the blast furnace is damaged.

2) When the water pressure (about 0.22MPa) in the cooling wall on the upper part of the furnace body is lower than the gas pressure (about 0.24MPa) in the furnace, it means that the gas in the furnace has flowed into the soft water system, that is, the gas will be collected in the expansion tank of the soft water system Or in the degassing tank, judge by detecting the gas concentration in the degassing tank of the degassing tank: if there is no gas in the degassing tank, it means that the cooling wall of the degassing system is normal and there is no damage. If there is gas in the degassing tank, then It shows that the cooling wall in the soft water system is damaged and there is internal leakage.

3) Judging by observing the water flow state in the flap flowmeter on the soft water return pipeline (the blast furnace is on the 16th floor stave soft water return pipeline, there are 180 flap flowmeters in total): if the flowing water is transparent, the cooling pipeline Normal, if the water flow in the flap flowmeter has air bubbles or white turbidity, the cooling wall containing the cooling water pipeline is damaged;

4) Analyze the test results of soft water quality. Under normal circumstances, in the soft water quality report, the pH value is stable at about 9.2 (the specified standard value is between 8-10), and the pH value continues to decrease slowly. Exclude a large amount of water change or a large amount of water replenishment in the soft water system ( Abnormal cause, a large amount of soft water leakage), it means that the cooling wall in the soft water system is damaged, and there is internal leakage, because the gas in the furnace enters the soft water system, the carbon dioxide in the gas dissolves into the water, and a chemical reaction occurs to form carbonic acid It is slightly acidic, resulting in a decrease in the pH of soft water. In this way, it is determined that the cooling wall in the cooling pipeline is damaged.

5) Observe whether there are water marks, Glauber's salt and other exudates on the eye plate of the blast furnace skin. If the blast furnace skin in the water leakage area has gas leakage points (for example: stave bellows, stave screw cover, etc.), the water entering the furnace will be carried out by the gas, and water marks and Glauber's salt will appear at the gas leakage points of the furnace skin. and other exudates.

Leakage steps:

Through the above method, it is determined that the cooling wall of the soft water system is damaged and there is internal leakage. By observing the leak detection method of the flap flowmeter on the outlet cooling water pipe of each cooling wall on the 16th floor cooling wall (there are 180 flap flowmeters in total), It can be determined which stave water pipe is damaged (there are 180 cooling water pipes in total), that is, the longitudinal direction;

Use the method of installing leak detection valves to check layer by layer. Determine which layer of the cooling wall the cooling water pipe leaks in, that is, horizontal;

1) Use a pressure gauge to pressurize the leak detection method: close the water inlet valve of the cooling water pipe of the cooling wall on the first layer, install a pressure gauge on the leak detection valve on the water inlet cooling water pipe of the cooling wall on the first layer of cooling wall, and start from the cooling wall of the first layer. From the 16th layer of staves, close the three-way valve layer by layer, which layer of staves has pressure relief, which means that the cooling water pipes of which layer of staves are damaged.

2) Close the water inlet and outlet valves of this cooling water pipe, and observe the water level in this cooling water pipe leaks to which layer it stops falling, which indicates that the cooling water pipe of the cooling wall on which layer is damaged, but in order to prevent the cooling wall from being burned due to water cut-off damage, this leak detection method is only suitable for use when the blast furnace is shut down.

Through the above method, it is possible to accurately determine which layer (horizontal) and which (longitudinal) stave is leaking, so as to quickly decompose, disengage, and maintain separately, so as to avoid affecting the normal production of the blast furnace.

Examples of production operations:

From January 3, 2012, according to the change trend of the pH value in the water quality report: from 9.2↘8.9↘8.1↘7.5; gas appeared in the degassing tank of the soft water system; observation found that the 132# cooling wall cooling water pipe soft water return pipeline turned over The water flow in the plate flowmeter has obvious air bubbles or white turbidity; the furnace skin leakage gas point in the 132# cooling wall leakage area has water traces, Glauber’s salt and other exudates; it was accurately judged when the wind was off on January 13, 2012 The 132# stave cooling pipe (longitudinal) of the blast furnace leaked water; on March 28, 2012, it was determined that the 132# cooling water pipe of the 15th stave was damaged by using the regular rest time; The water is used for maintenance treatment, and the other 1-14 staves are connected in series, and the 132# cooling water pipe of the 14-16 staves continues to circulate and cool with soft water to ensure the normal cooling of the blast furnace cooling system. the

Claims (2)

1. leak detection and method of disposal that is used for blast furnace soft water closed circulation cooling system is characterized in that: the Disposal Measures that is divided into leak detection and mending-leakage:

Step 1 leak detection is judged:

1) the expansion drum liquid level of soft water system, normal range be at 3.1-3.4 rice, when being lower than 3.1 meters, namely needs frequent moisturizing, shows that water in the cooling stave bleeds in the stove, and blast furnace cooling stave exists damaged;

2) detect coal gas in the expansion drum of soft water system or the degassing vessel, show that the soft water pressure of upper shaft is lower than the interior gas pressure of upper shaft stove, coal gas is altered in the stove, and namely coal gas is altered by the cooling stave of breakage and entered in the soft water system, and cooling stave has breakage; Circulating pressure in this moment upper shaft cooling stave is at 0.20-0.22mPa, and in the stove upper shaft gas pressure at 0.23-0.24mPa;

3) the soft water airtight circulating cooling system cooling stave is vertical 16 layers, establishes 45 cooling staves for horizontal every layer, establishes 4 water-cooled tubes in the every cooling stave, and 180 water-cooled tubes are arranged altogether; Adopt 180 turnover panel under meter Real-Time Monitorings, the current in the turnover panel under meter have bubble or gonorrhoea, show that the cooling stave that cooling stave vertically comprises this cooling water pipeline has breakage;

4) soft water check pH normal value when the pH value is continued slowly to reduce by 9.2 ↘, 8.9 ↘, 8.1 ↘ 7.5, determines namely that coal gas is scurried in the soft water system in the stove at 8-10, carbonic acid gas in the coal gas dissolves in the water, form carbonic acid and be slightly acidic, cause the reduction of pH value, show that cooling stave has breakage;

5) observe the exudate that the shell of blast furnace eye slab has water mark, saltcake, namely determine to enter the interior water of stove and taken out of by coal gas, carrying the grouting material of stove intracutaneous secretly, namely reveal coal gas point water seepage mark, saltcake at the stove skin, show that cooling stave has breakage;

Step 1 leak detection is disposed:

Vertically dispose: observe the turnover panel under meter on every cooling stave water outlet of the 16th layer of cooling stave water-cooled tube, determine that the position of cooling stave water pipe is damaged, namely implement to dispose;

Laterally dispose: its 1 use setting pressure table is suppressed leak hunting method, namely successively closes T-valve, and which layer cooling stave has the pressure of rushing down phenomenon, illustrates that then which layer cooling stave water-cooled tube has disrepair phenomenon; It 2 closes this root water-cooled tube Inlet and outlet water valve, observes water level in this root water-cooled tube and leaks to which layer and stop to descend, and illustrates that then which layer cooling stave water-cooled tube has disrepair phenomenon; Namely implement to dispose.

2. described method according to claim 1 is characterized in that: the leak detection in the large blast furnace of turnover panel under meter is arranged on the suitable SWR road of the method.