JPH11352003A - Gas leakage detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas leakage detector which can detect a leak, even when the pressure on the side of an attached machine to be cooled is higher than the pressure of cooling water. SOLUTION: This gas leakage detector comprises a pot inlet piping 4, a pot body 6, a water level detector 7, a deposite draw-out piping 13, a pot outlet piping 17, and a water-filling piping 18. The pot inlet piping is coupled with the water-cooled jacket of an ammonia injection nozzle 3 coupled with a main cooling water supply pipe 2, and the pot outlet piping 17 is coupled with a main cooling water return pipe 5. Exhaust gas infiltrating from the water-cooled jacket is taken into the pot body, and the change of water level in the pot body is detected by the detector 7 thus detecting the occurrence of a gas leak.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas leak detecting device for detecting a gas leak to a cooling water circulating system of a boiler or an accessory of a chemical device, and is particularly suitable for detecting a leak of high pressure gas to a cooling water circulating system. The present invention relates to a simple gas leak detection device.

[0002]

2. Description of the Related Art A conventional example will be described using a boiler as an example. FIG. 2 shows a cooling system for a boiler circulation pump, an air compressor, an air suction fan, and a motor, which are accessories of the boiler. In this figure, 21 is a cooling water circulation pump, 22 is a cooling water supply mother pipe, 23 is a boiler circulation pump,
24 is an air compressor, 25 is an air suction fan, 26
Denotes a motor, 27 denotes a flow detector, 28 denotes an inlet stop valve, 29 denotes an outlet stop valve, 30 denotes a cooling water return mother pipe, and 31 denotes a cooling water cooler.

[0003] As is apparent from this figure, the cooling system of the auxiliary equipment of the boiler supplies the cooling water supplied from the cooling water circulating pump 21 through the cooling water supply mother pipe 22 and the inlet stop valve 28 to each of the auxiliary equipment 23, 24. , 25, and 26, the cooling water after the equipment cooling is joined to the cooling water return mother pipe 30 through the flow rate detector 27 and the outlet stop valve 29, and the cooling water itself is cooled by the cooling water cooler 31. The circulation system returns to the cooling water circulation pump 21, and the cooling water is used repeatedly.

[0004] The pressure of the cooling water flowing through the cooling water circulation system is usually adjusted to 6 atm, and the pressure of the cooling water is higher than the pressure of each of the attached devices 23, 24, 25 and 26. If a leak occurs due to damage to the piping in the circulation system, the cooling water blows out of the piping, and the amount of cooling water passing through each of the attached devices 23, 24, 25, and 26 decreases. Therefore, each of the attached devices 23, 24, 25,
A leak can be detected from a change in the output signal of the flow rate detector 27 installed on the outlet side of the sensor 26. Further, since the cooling water is blown out of the circulation system when a leak occurs, it is not necessary to consider deterioration of water quality and contamination of the inner surfaces of the cooling water supply mother pipe 22 and the return mother pipe 30.

[0005]

In the meantime, ammonia is injected from an ammonia injection nozzle into an exhaust gas channel from a furnace outlet of a boiler or the like in order to remove harmful substances in the exhaust gas. In order to prevent the thermal damage of the circulating system, it has been studied to cool the distal end thereof with cooling water flowing through the circulation system.

If the pressure of the exhaust gas flowing through the outlet pipe of the pressure vessel is higher than the pressure of the cooling water flowing through the circulation system (about 6 atm), damage to the cooling portion of the ammonia injection nozzle will cause an accessory to be cooled. Unlike the case where the equipment is the boiler circulation pump 23 or the like, the cooling water does not squirt out of the system, but the exhaust gas in the furnace outlet pipe enters the cooling water circulation system.

[0007] However, in the conventional technique, a change in the amount of cooling water passing through the accessories 23, 24, 25, 26 to be cooled is detected by a flow rate detector installed at the outlet side of each of the accessories 23, 24, 25, 26. Since the detection is performed at 27 and the presence or absence of a leak is detected, if exhaust gas in the furnace outlet pipe enters the cooling water circulation system, there is a problem that the presence or absence of a leak cannot be accurately detected. . That is, since the flow rate detector 27 detects the total flow rate of the cooling water and the gas, even if a leak occurs, the detected flow rate of the flow rate detector 27 does not seem to decrease.

Further, when the conventional technique is applied to cooling of an ammonia injection nozzle, when the cooling portion of the ammonia injection nozzle is damaged, the exhaust gas in the furnace outlet pipe directly enters the cooling water circulation system. Because of this, a large amount of exhaust gas easily enters the cooling water circulation system after damage occurs, causing cavitation in the pump, corrosive gas such as SO ₂ contained in the exhaust gas corroding piping and attached equipment, Further, failure of the cooling water circulation pump 21 due to intrusion of solid components such as combustion ash and fluidized bed medium contained in the exhaust gas is likely to occur.

In the above description, cooling of the ammonia injection nozzle has been described as an example. However, in the above-described conventional technique, a gas having a pressure higher than the pressure of the cooling water is handled by using the cooling water flowing through the cooling water circulation system. Similar disadvantages arise in any case of cooling the equipment.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned deficiencies of the prior art, and has as its object to prevent leakage even when the pressure of the accessory to be cooled is higher than the pressure of the cooling water. It is an object of the present invention to provide a gas leak detection device which can surely detect a gas leak and can prevent various inconveniences caused by a leak.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a gas leak detecting device attached to a cooling water circulating system of a boiler device, by connecting the gas leak detecting device to a cooling water circulating system through a pot inlet pipe and a pot outlet pipe. A connected pot body, a water-filled pipe for injecting a predetermined amount of cooling water into the pot body, and a water level detection device provided in the pot body,
A deposit extraction pipe for discharging deposits deposited on the bottom of the pot body to the outside of the pot body is provided.

When the pot body is provided in the cooling water circulation system and the pot body is full during normal operation and cooling water is supplied, leak gas enters the pot body when a gas leak occurs, and the water level in the pot body is reduced. To decrease,
By detecting this, a gas leak can be detected. In addition, since corrosive gas and solid matter contained in the leaked gas can be stored in the pot body,
It is possible to prevent the outflow of these harmful substances to the pot outlet pipe and beyond, thereby preventing corrosion of the pipes and damage to the pumps.

The cross-sectional area of the pot body is sufficiently larger than the cross-sectional area of the pot inlet pipe so that the above function can be exhibited even when a large amount of corrosive gas leaks into the cooling water circulation system. Is preferred.

The pot inlet pipe is attached to the pot body so that the inside of the pot body is full during normal operation so that cooling water can pass therethrough so that a gas leak can be detected immediately. Preferably, the position is above the mounting position of the pot outlet pipe with respect to the pot main body and below the mounting position of the upper detection pipe provided with the water level detecting device.

Further, since solids contained in the leak gas are settled and deposited on the bottom of the pot main body, in order to prevent these harmful substances from flowing out after the pot outlet pipe,
It is preferable that the pot outlet pipe be connected to a lower portion of a side surface of the pot body instead of a bottom surface.

Further, it is preferable that a vent pipe is connected to the top of the pot main body and a sediment discharge pipe is connected to the bottom of the pot main body in order to discharge the harmful substances that have entered.

In addition, the gas leak detection device of this embodiment includes:
An alarm device for notifying a worker of the occurrence of a gas leak based on an output signal from the water level detecting device, or a shutoff device for automatically shutting off a cooling water circulation system may be provided.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a gas leak detecting device according to the present invention will be described below with reference to FIG. In FIG.
An example is shown in which a gas leak detection device according to the present invention is installed in a system for cooling an ammonia injection nozzle for injecting ammonia into a furnace outlet pipe of a boiler using cooling water flowing through a cooling water circulation system.

In FIG. 1, 1 is a cooling water circulation pump, 2
Is a cooling water supply pipe, 3 is an ammonia injection nozzle, 4 is a pot inlet pipe, 5 is a cooling water return pipe, 6 is a pot body,
7 is a water level detector, 8 is a cooling water cooler, 9 is an inlet stop valve, 1
0 is an outlet stop valve, 11 is a furnace outlet pipe, 12 is a vent pipe, 13 is a sediment discharge pipe, 14 is a flow detector, 1
5 is a boiler accessory such as a boiler circulation pump, an air compressor, an air suction fan or a motor, 16 is a boiler circulation pump, 17 is a pot outlet pipe, 18 is a water-filled pipe, and the pot inlet pipe 4, The gas leak detection device includes the pot body 6, the water level detector 7, the inlet stop valve 9, the outlet stop valve 10, the vent pipe 12, the sediment discharge pipe 13, the pot outlet pipe 17, and the water filling pipe 18.

The pot body 6 has a cross-sectional area sufficiently larger than the cross-sectional area of the pot inlet pipe 4 so that a large amount of leaked gas can be stored in the cooling water circulation system. The pot body 6 has a pot inlet pipe 4 at an upper part of a side face, a pot outlet pipe 17 and a water filled pipe 18 at a lower part of a side face, and a vent pipe 12 at a top part.
However, the sediment extraction pipe 13 is connected to the bottom. The mounting position of the pot inlet pipe 4 is set above the mounting position of the pot outlet pipe 17 with respect to the pot body 6 and below the mounting position of the upper detection pipe 7a provided with the water level detector 7.

The value detected by the water level detector 7 is displayed on a meter, and an operator can detect the presence or absence of a gas leak by monitoring the display of the meter. Others
An alarm device is activated based on the output signal of the water level detector 7 to notify a worker of the occurrence of a gas leak, or a cutoff automatically set in the cooling water circulation system based on the output signal of the water level detector 7. It is also possible to load a function such as shutting off the device.

A water cooling jacket 3a is provided on the outer periphery of the distal end of the ammonia injection nozzle 3, and the cooling water supply mother pipe 2 and the pot inlet pipe 4 are connected to the water cooling jacket 3a. The tip of the ammonia injection nozzle 3 including a part of the water cooling jacket 3a is inserted into the furnace outlet pipe 11 as shown in FIG.
H ₃ ) is injected into the exhaust gas.

Hereinafter, the flow of the cooling water in the cooling water circulation system configured as described above and the function of the gas leak detection device according to the embodiment will be described.

The interior of the pot body 6 is filled with water from a water-filled pipe 18. In this state, the cooling water discharged from the cooling water circulation pump 1 passes through the cooling water supply mother pipe 2, passes through the boiler circulation pump 16 and other boiler accessories 15, and the inlet stop valve 9, and the water cooling jacket of the ammonia injection nozzle 3. 3a.
The cooling water that has flowed out of the ammonia injection nozzle 3 enters the pot body 6 through the pot inlet pipe 4 and joins the cooling water return mother pipe 5 via the pot outlet pipe 17 and the outlet stop valve 10.
Further, the cooling water return mother pipe 5 has a boiler circulation pump 1
The cooling water after cooling the 6 and other boiler accessories 15 is also joined. The cooling water that has entered the cooling water return mother pipe 5 is
The cooling water is cooled to a predetermined temperature by the cooling water cooler 8 and is recirculated by the cooling water circulation pump 1.

The exhaust gas of the pressurized fluidized bed boiler flowing through the furnace outlet pipe 11 has a pressure of about 10 atm and a temperature of 865 ° C., which is high pressure and high temperature. The exhaust gas contains combustion ash and a fluidized bed medium. For this reason, the portion of the ammonia injection nozzle 3 inside the furnace outlet pipe 11 is exposed to high-temperature gas and is susceptible to wear and damage due to combustion ash and a fluidized bed medium.

When the water cooling jacket 3a is damaged, the exhaust gas leaks into the cooling water circulation system because the exhaust gas pressure (about 10 atm) is higher than the cooling water pressure (about 6 atm). The exhaust gas leaked into the cooling water circulation system enters the pot body 6 via the pot inlet pipe 4. As mentioned above,
Since the pot body 6 is full of water, when the leaked exhaust gas enters the pot body 6, the exhaust gas is
And lowers the water level in the pot body 6. The water level detector 7 detects the lowering of the water level and detects that there is a gas leak. Also, an alarm (not shown) or a cooling water cutoff device is operated. In this case, at the time of normal operation, the inside of the pot body 6 is filled with water and the cooling water is supplied, and the mounting position of the pot inlet pipe 4 with respect to the pot body 6 is changed from the mounting position of the pot outlet pipe 17 with respect to the pot body 6. The upper part is also located below the mounting position of the upper detection pipe 7a provided with the water level detector 7, so that the occurrence of gas leak can be detected quickly.

Since the cross-sectional area of the pot body 6 is formed larger than the cross-sectional area of the pot inlet pipe 4, even when a large amount of gas leaks, exhaust gas enters the pot outlet pipe 17 from the pot body 6. Never. In addition, the flow rate in the pot body 6 is reduced due to the large cross-sectional area of the pot body 6, and the pot outlet pipe 17 is taken out from the lower side surface instead of the upper part of the pot 6, so that the interior of the pot body 6 is settled. Since it is possible to prevent the incoming combustion ash and fluidized bed medium from flowing into the pot outlet pipe 17,
Contamination of the cooling water in the cooling water circulation system can be prevented.

After the occurrence of the gas leak, the inlet stop valve 9 and the outlet stop valve 10 are closed to separate them from the cooling water circulation system and the like. First, the bend pipe 12 at the upper part of the pot body 6 is opened to open to the atmosphere. Next, the sediment extraction pipe 13 at the bottom
Then, the deposit accumulated at the bottom of the pot body 6 and the cooling water remaining in the water cooling jacket 3a and the pot body 6 are blown to repair the gas leak portion. In this case, since the vent pipe is connected to the top of the pot body 6 and the sediment discharge pipe 13 is connected to the bottom, the exhaust gas, the sediment, and the residual cooling water can be reliably blown.

After the repair, the inside of the pot body 6 and the inside of the water cooling jacket 3a provided around the ammonia injection nozzle 3 are filled with make-up water from the water filling pipe 18, and then the inlet stop valve 9 and the outlet stop valve 10 are filled. Open and connect to the cooling water circulation system. Thereby, the cooling water circulation system can be restarted.

In the above embodiment, the gas leak detecting device applied to the cooling section of the ammonia injection nozzle 3 has been described as an example. However, the gist of the present invention is not limited to this. The present invention can be applied to any cooling unit that may enter.

[0031]

As described above, according to the present invention,
A gas leak detection device, a pot body connected to a cooling water circulation system via a pot inlet pipe and a pot outlet pipe, a water-filled pipe for injecting a predetermined amount of cooling water into the pot body, and a water level detection provided on the pot body. Since the apparatus and the sediment withdrawal pipe for discharging the sediment deposited on the bottom of the pot body to the outside of the pot body were configured, during normal operation, the inside of the pot body was filled with water during the normal operation, and cooling water was passed through.
Gas leaks can be detected by detecting a drop in the water level in the pot body with a water level detector. Also,
Corrosive gas and solid matter contained in the leaked gas can be stored in the pot body, so that these harmful substances can be prevented from flowing out after the pot outlet piping, preventing corrosion of piping and damage to pumps. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a system diagram of a cooling water circulation system and the like including a gas leak detection device according to an embodiment.

FIG. 2 is a system diagram of a cooling water circulation system and the like including a gas leak detection device according to a conventional example.

[Explanation of symbols]

 Reference Signs List 1 cooling water circulation pump 2 cooling water supply mother pipe 3 ammonia injection nozzle 4 pot inlet pipe 5 cooling water return mother pipe 6 pot 7 water level detector 8 cooling water cooler 9 inlet stop valve 10 outlet stop valve 11 furnace outlet pipe 12 vent pipe 13 Sediment extraction pipe 14 Flow rate detector 15 Boiler accessory equipment 16 Boiler circulation pump 17 Pot outlet pipe 18 Water-filled pipe

Claims (6)

[Claims] 1. A pot body connected to a cooling water circulation system via a pot inlet pipe and a pot outlet pipe, a water-filled pipe for injecting a predetermined amount of cooling water into the pot body, and a water level provided on the pot body. A gas leak detection device comprising: a detection device; and a deposit extraction pipe for discharging deposits deposited on a bottom portion of the pot body to outside the pot body. 2. The gas leak detection device according to claim 1, wherein a cross-sectional area of the pot main body is larger than a cross-sectional area of the pot inlet pipe. 3. The gas leak detection device according to claim 1, wherein a mounting position of the pot inlet pipe with respect to the pot main body is higher than a mounting position of the pot outlet pipe with respect to the pot main body, and A gas leak detecting device, wherein the gas leak detecting device is located below a mounting position of an upper detecting pipe provided. 4. The gas leak detection device according to claim 1, wherein the pot outlet pipe is connected to a lower portion of a side surface of the pot body. 5. The gas leak detection device according to claim 1, wherein a vent pipe is connected to a top of the pot body, and the deposit extraction pipe is connected to a bottom of the pot body. apparatus. 6. The gas leak detection device according to claim 1, further comprising an alarm device that operates in response to an output signal from the water level detection device or a cutoff device for the cooling water circulation system. .