JPH0252901A - Detecting method of leaks on boiler tube in coke dry type fire extinguisher - Google Patents

Abstract

PURPOSE:To detect leaks on boiler tubes early and accurately by monitoring and comparing the moisture content of cooling gase at the inlet with that at the outlet of a waste heat boiler. CONSTITUTION:An inlet moisture content meter 21 that measures the moisture content of cooling gas is installed at the inlet of a waste heat boiler 11 and an outlet moisture content meter 22 that measures the moisture content of cooling gas on a gas duct 13 at the outlet. A moisture content measuring device 23 is provided to calculate and indicate the measured moisture content values of the inlet and outlet moisture content meters 21 and 22. The moisture content measuring device 23 measures the moisture contents of the cooling gases in both the inlet and outlet of the waste heat boiler 11 at the same time. [DELTAM=Mo-Mi] is calculated, where Mi % represents the moisture content measured by the moisture content meter at the inlet of the waste heat boiler, and Mo % the moisture content measured by the moisture content meter at the outlet. When DELTAM becomes larger than zero, it is judged that leaks occur on the boiler tubes of the waste heat boiler.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for detecting holes in a boiler tube in coke dry extinguishing equipment.

<Prior Art> In general, coke dry extinguishing equipment consists of a vertical cooling tower l, a buried flue, and a waste heat boiler II, as shown in Fig. The red hot coke placed in the bucket 6 is carried by a crane 17 and charged into the charging port 2 of the cooling tower 1, and is cooled by blowing inert gas at around 180°C from the bottom of the cooling tower 1 as a cooling gas. It is cooled and conveyed out by a belt conveyor 7 through a cutting gate 5 and a chute 6 provided at the bottom.

On the other hand, the cooling gas heated by the red-hot coke in the cooling tower 1 is discharged to the flue 9 via the annular flue 8, and is removed by 1! ! !
The waste heat is introduced into the waste heat boiler 11 via the waste heat boiler 110 and exchanges heat with the water in the boiler tube 12, and the sensible heat is recovered to generate steam. The coke breeze is discharged, the pulverulent coke is removed by a cyclone 14, the pressure is increased by a circulation fan 15, and the gas is turned into cooling gas again, which is blown into the cooling tower 1 and used for circulation.

Note that during the circulation process of this cooling gas, air is injected from the combustion air hole 18 at the entrance of the flue 9 to adjust combustible gas components such as hydrogen gas and CO gas in the cooling gas. The cooling gas, whose amount has increased due to the injected air and hydrogen gas generated by the red-hot coke, is radiated from the diffusion pipe 19 or recovered as fuel.

By the way, the outer surface of the boiler tube 12 of the waste heat boiler 11 is abraded and thinned by coke dust in the cooling gas. Furthermore, the inner surface of the tube is corroded by the pure water flowing through the boiler tube 12, resulting in thinning.

As described above, the boiler tube 12 is thinned from both the inner and outer surfaces, and in some cases, holes are formed in the tube, causing problems such as high-pressure water and high-pressure steam inside the tube spouting out of the tube.

The boiler tubes 12 are arranged at narrow intervals of, for example, 102 mm x 125 mm+ within the waste heat boiler 11, so if high-pressure water or high-pressure steam spouts out from any of the boiler tubes 12, the spouted water generated at one location A situation occurs in which high-pressure steam and high-pressure steam impinge on the outer surface of other healthy adjacent tubes at high pressure and high speed, scraping the tube body and creating holes. The damage will be expanded.

In addition, the sulfur compounds contained in the cooling gas react with the spouted water and steam to generate sulfuric acid, which causes the boiler tube 12
A problem also arises in that the outer surface and gas duct openings 3 are corroded.

Therefore, it is necessary to detect the occurrence of a hole in the boiler tube 12 at an early stage, and if a hole occurs, to quickly replace and repair the boiler tube 12.

By the way, as a method for detecting the occurrence of a hole in the boiler tube 12 of the waste heat boiler 11 and the mixing of water or steam into the cooling gas, conventional methods have been used, for example, in
As disclosed in Japanese Patent No. 15433, a method has been proposed for determining damage to a boiler tube by comparing the steam generation flow rate of the boiler and the feed water flow rate and detecting an imbalance therebetween.

There is also a method in which water or steam leaking into the cooling gas reacts with red-hot coke in the cooling chamber as shown in equation (1) below, and changes in the resulting hydrogen gas are measured.

C+ II! 0-CO+11! −−−−−−・−・
−・−・・−・−・−・−・・・・・(1) <41 problems to be solved by the invention> However, the former method of Japanese Patent Publication No. 15433/1983 is based on the steam generation flow rate and the water supply flow rate. Due to the error in the flowmeter that measures the flow rate, there is a drawback that holes in the boiler tube cannot be detected during periods when the holes are small.

In other words, the flow rate needle usually has an error of about 0.5%,
For example, in a waste heat boiler of about 30 L/h, it cannot be said that there is a difference between the steam flow rate needle and the feed water flow meter unless it is 0.3 t/h or more. A leak cannot be determined.

In addition, in the latter method of determining based on changes in hydrogen gas, hydrogen gas is also generated from the red-hot coke charged into the cooling tower.
The amount changes depending on the carbonization state of the red-hot coke, so
When charging poorly carbonized red hot coke, a large amount of hydrogen gas is generated, which cannot be detected during periods when the holes in the boiler tube are small.

Table 1 shows an example of the analysis results of the components of the cooling gas.

Table 1 (Capacity %) As shown in this example, I+ is 3.6% to 16.4%
This makes it impossible to detect small holes in the boiler tube from the hydrogen gas content.

The present invention has been made to solve the problems of the prior art as described above, and an object of the present invention is to provide a method for early and reliably detecting holes in a boiler tube in coke dry extinguishing equipment. do.

<Means for Solving the Problems> The present invention is a method for detecting holes in a boiler tube in coke dry extinguishing equipment, which detects waste heat boiler population and moisture in cooling gas for coke dry extinguishing at the outlet, This is a method for detecting a hole in a boiler tube in a coke dry fire extinguishing equipment, which is characterized in that the point at which a difference occurs between these measured values is determined to be a hole in the boiler tube.

<Function> In general, the cooling gas used in coke dry extinguishing equipment is an inert gas, so it usually does not contain moisture. However, the cooling gas circulates while cooling the red-hot coke. In order to reduce the concentration of combustible components in the air or cooling gas from which hydrogen gas generated from red-hot coke leaks, the combustion air pipe 1 shown in Figure 3 above is used.
Air forcedly blown through 8 and L+1/20x-II□0-・-・-・・・・・
・・・−・−・・−・・・・−・・・・・・・・・・(
2) The moisture generated by the reaction and the moisture originally contained in the air will mix.

In addition, the moisture in the cooling gas generated in this way is
By reacting with red-hot coke, that is, according to equation (1) above, a part of it is decomposed into hydrogen gas and CO gas and fluctuates.

Furthermore, the amount of moisture contained in the air is influenced by the weather. That is, for example, during the dry season and low temperature in the winter, it changes to about 5 g/N+*ff (0.62 volume %), and in the hot summer, it changes to about 20 g/Nm' (2.5 volume %). Contributes to fluctuations in moisture in the gas.

FIG. 4 is an example in which a moisture meter is installed at the outlet of a waste heat boiler to measure moisture in cooling gas. In this example, it can be seen that the moisture content varies between 1.0 and 4.9%.

On the other hand, if there is a hole in the boiler tube and water leaks at a rate of 100 kg/h, for example, in a coke dry fire extinguishing system with a coke processing capacity of 56 t/h, approximately 1000 rrf of cooling gas system volume will be released outside the system. If the amount of surplus gas is 200ONm"/h, the increase in moisture in the cooling gas will be 4.1%, so water or steam leakage due to holes in the boiler tube can be avoided by setting the moisture measurement point to one location. Therefore, it cannot be detected accurately.

Therefore, if you install a moisture meter at the inlet of the waste heat boiler and measure the moisture in the cooling gas at the inlet of the waste heat boiler, you can measure the amount of moisture that the cooling gas itself brings into the waste heat boiler. Therefore, if the amount of moisture at the outlet of the waste heat boiler fluctuates, by comparing the two, it is possible to determine whether the change is due to a hole in the boiler tube.

That is, the value measured by the moisture meter at the waste heat boiler's population is M+(%), and the value measured by the moisture meter at the outlet is M, (%), and the difference ΔM between them is calculated by the following equation (3).

6M-M, -Ml-・〜・〜・・−・・−・〜・〜
・−・・・−・−・−(3) Therefore, this 6M is O
When the hole becomes larger, it is determined that a hole has occurred in the boiler tube.

<Examples> Examples of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the method of the present invention. In FIG. 1, the same members as in the conventional example are designated by the same reference numerals, and the explanation thereof will be omitted.

In the figure, 21 is an inlet moisture meter attached to the inlet of the waste heat boiler 11 to measure the moisture in the cooling gas.

Reference numeral 22 denotes an outlet moisture meter that is attached to the gas duct 13 at the outlet of the waste heat boiler 11 and measures the moisture in the cooling gas.

Further, 23 is a calculation display device that calculates and displays the moisture measurement value of the inlet moisture meter 21 and the moisture measurement value of the outlet moisture meter 22.

Using the moisture measuring device configured as described above, the moisture in the cooling gas was measured simultaneously at the inlet and outlet of the waste heat boiler 11.

Therefore, at a certain point, 50 kg of water was sprayed into the gas duct 13 at the outlet of the waste heat boiler 11, and the difference between the two at that time was determined using the above equation (3). The results are shown in FIG.

As is clear from this figure, the difference between the two up to the time of water spraying was within 0 ± 0.5%, but after the time of water spraying, it became approximately 2%, and this value is comparable to the amount of water sprayed. I know what you're doing.

From the results of this experiment, it is clear that when 100 kg/h of water is sprayed, the value of the difference becomes even larger.
It goes without saying that it is possible to detect leakage of water or steam of less than kg/h.

By using the present invention in this way, even if there is a small hole in the boiler tube, it can be reliably detected.

<Effects of the Invention> As explained above, according to the present invention, by comparing and monitoring the moisture in the cooling gas at the inlet and outlet of the waste heat boiler, holes in the boiler tube can be detected early and reliably. Can be detected.

Therefore, since holes in the boiler tube can be repaired while they are still small, the time and cost required for boiler tube repair and replacement can be significantly reduced. This increases the operating rate of the waste heat boiler of coke dry extinguishing equipment, which has a high frequency of occurrence, and contributes to its stable operation.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing an embodiment according to the present invention, Fig. 2 is a characteristic diagram showing an example of measurement of water difference in cooling gas at the population and outlet of a waste heat boiler, and Fig. 3 is a coke dry type FIG. 4, which is a block diagram showing a conventional example of fire extinguishing equipment, is a characteristic diagram showing changes over time in moisture in cooling gas at the outlet of a waste heat boiler. ■... Cooling tower, 9... Flue. 11...waste heat boiler, 12...boiler tube. 13... Gas duct, 21... Inlet moisture meter 2
2...Outlet moisture meter, 23...Calculation display device.

Claims (1)

[Claims] A method for detecting holes in boiler tubes in coke dry extinguishing equipment, in which moisture in the cooling gas for coke dry extinguishing at the inlet and outlet of a waste heat boiler is detected, and the point at which a difference occurs between these measured values is detected in the boiler tube. A method for detecting a hole in a boiler tube in a coke dry extinguishing equipment, characterized by determining that there is a hole in the boiler tube.