JP2000213704A - Boiler drainage device using blowdown tank and operation method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the sealed water level in a blowdown tank, and to avoid that steam flows out from an opening, even if superheated steam flows in the blowdown tank, causing the evaporation of the drain water that stays in the blowdown tank. SOLUTION: In a blowdown tank 1 which is provided in the drainage system of a boiler and introduces steam and drain to perform centrifugal separation, a steam discharging pipe 5 which discharges the separated steam from the top part, and a siphon type drain pipe 6 which is provided with one end opening soaked downward in the drain in order to prevent the steam from flowing out unexpectedly, are provided. There are provided a cooling water injecting piping 8 which injects cooling water into the blowdown tank 1, and a drain cooling water shut-off valve 9 which controls the amount of the cooling water to be injected into the blowdown tank 1 from the cooling water injecting piping 8. The cooling water is injected into the blowdown tank 1 from the cooling water injecting piping 8 in advance, before the superheated steam flows into the blowdown tank 1, so as to prevent the discharge of the steam from the drain pipe 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a boiler drainage system, and more particularly to a boiler blowdown tank drainage cooling system and a drainage cooling control system.

[0002]

2. Description of the Related Art FIG. 3 shows a drainage system diagram of a blowdown tank of a conventional boiler. In a conventional boiler blowdown tank drainage system, a blowdown tank 1, a drainage cooler 2 for cooling drainage from the tank 1, and a drainage temperature provided in a cooling water pipe 3 for supplying the drainage cooler 2 are provided. Control valve 4 and exhaust pipe 5 provided at the top of blowdown tank 1
And a siphon type drain pipe 6 for connecting the blowdown tank 1 and the drain cooler 2, and a drain thermometer 7 provided on the downstream side of the cooler 2 of the drain pipe 6.

When the boiler is started, drain and steam flow from the drain system connected to the blow-down tank 1 into the blow-down tank 1, and after the steam and the drain are centrifuged,
The steam is discharged from the exhaust pipe 5, and the drain is discharged from a siphon-type drain pipe 6 below the blowdown tank 1.

The drain water discharged from the blowdown tank 1 is sent to a drain cooler 2, and the drain water is controlled by a drain temperature control valve 4 provided in a cooling water pipe 3 based on a command from a control device 10. The temperature of the waste water is lowered to a set value (about 60 ° C.) or less by adjusting the injection amount of the cooling water and discharged from the drain pipe 6.

[0005] In the blowdown tank 1, an opening with the drain pipe 6 facing downward is immersed in the drain, and the seal effect of the drain water is used, so that steam flows out of the outlet of the drain pipe 6 carelessly. Is preventing that.

[0006]

In the above prior art, when superheated steam flows from the boiler into the blowdown tank 1, the drain water retained in the blowdown tank 1 is evaporated and discharged from the exhaust pipe 5. Therefore, the seal water level cannot be maintained, and there is a problem that steam flows out from the opening of the drain pipe 6.

An object of the present invention is to maintain a seal water level in a blow-down tank even if superheated steam flows into a blow-down tank and drain water retained in the blow-down tank evaporates. Do not let it flow out of the exit.

[0008]

SUMMARY OF THE INVENTION The object of the present invention is to provide a steam exhaust pipe provided in a drainage system of a boiler for introducing steam and drain and centrifuging the steam and then discharging the steam, and for inadvertently discharging steam. In a boiler drainage device using a blowdown tank provided with a siphon-type drain pipe provided by immersing one end opening downward in the drain to prevent the cooling, the cooling water is injected into the blowdown tank. The problem is solved by a blowdown tank device provided with a water injection pipe and a control device for controlling the amount of cooling water injected from the cooling water injection pipe into the blowdown tank.

Further, the blowdown tank device employs an operation method in which cooling water is injected into the blowdown tank before the superheated steam flows into the blowdown tank, thereby preventing the steam from flowing out of the drain pipe. .

According to the present invention, by injecting cooling water directly into the blowdown tank, even if superheated steam flows into the blowdown tank, it is possible to maintain the seal water level in the blowdown tank and to discharge water. The outflow of steam from the opening of the tube can be prevented.

The boiler of the present invention is a boiler used for a thermal power plant or a nuclear power plant, which comprises a water tube wall constituting a wall surface of a furnace and a superheater disposed downstream of the furnace, etc. Such as a recovery boiler.

[0012]

Embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, a blowdown tank drainage system of a boiler and an exhaust heat recovery boiler using a furnace (not shown) according to an embodiment of the present invention includes a blowdown tank 1 and drainage cooling for cooling drainage from the tank 1. The drainage temperature control valve 4 provided in the cooling water pipe 3 for supplying the water to the drainage cooler 2, the exhaust pipe 5 provided at the top of the blowdown tank 1, the blowdown tank 1, and the drainage cooler 2 are connected Siphon type drain pipe 6 and drain pipe 6
In addition to the drainage thermometer 7 arranged on the downstream side of the cooler 2 provided in the cooling water supply system, a cooling water supply system 8 branched from the cooling water pipe 3 upstream of the drainage temperature control valve 4 of the drainage cooling water system is provided. The cooling water can be directly injected from the cooling water supply system 8 into the blowdown tank 1.

The drainage cooling water supply system 8 has a drainage cooling water cutoff valve 9 connected to a cooling water pipe 3 upstream of the drainage temperature control valve 4.
Is installed. Based on a command from the control device 10, the drain / cooling water shutoff valve 9 opens before the superheated steam flows into the blowdown tank 1, and maintains the open state until the flow of the superheated steam and the drain ends. At this time, the temperature of the waste water discharged from the opening immersed in the drain of the drain pipe 6 is set to a set value (about 60 ° C.).
) The cooling water is injected by adjusting the opening of the drainage temperature control valve 4 as described below.

Then, superheated steam flows from a boiler (not shown) into the blowdown tank 1,
Even if the drain water retained in the inside evaporates, the drain cooling water shutoff valve 9 is kept open and the blowdown tank 1
By maintaining the level of the stagnant water in the inside, the steam is prevented from flowing out from the opening of the drain pipe 6 immersed in the drain.

In the embodiment shown in FIG. 2, a blow-down tank cooling water supply system 8 for injecting cooling water directly into the blow-down tank 1 is provided downstream of the drainage temperature control valve 4 of the cooling water pipe 3. It is. In this case as well, as in the example shown in FIG. 1, the drainage temperature control valve 4 is opened by the control device 10 before flowing into the blowdown tank 1, and its opening is kept constant before the superheated steam flows. The cooling water injection amount is controlled so that the temperature of the waste water discharged from the opening immersed in the drain of the drain pipe 6 is maintained at a set value (about 60 ° C.) or less until the inflow of the steam and the drain ends.

The superheated steam is supplied to the blowdown tank 1
The blowdown tank cooling water supply system 8 is kept open even if it begins to flow into the tank, the level of the stagnant water in the blowdown tank 1 is maintained, and the steam flows out from the opening immersed in the drain of the drain pipe 6. Can be prevented.

[0017]

According to the present invention, by injecting the cooling water directly into the blowdown tank, the level of the water retained in the blowdown tank can be maintained even if the superheated steam flows into the blowdown tank. Steam does not flow out of the opening immersed in the drain of the drain pipe.

[Brief description of the drawings]

FIG. 1 is a diagram showing a blowdown tank system of the present invention.

FIG. 2 is a diagram showing a blowdown tank system of the present invention.

FIG. 3 is a diagram showing a conventional blowdown tank system.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Blowdown tank 2 Drain cooler 3 Cooling water pipe 4 Drain temperature control valve 5 Exhaust pipe 6 Drain pipe 7 Drain thermometer 8 Cooling water supply system 9 Drain cooling water shutoff valve 10 Control device

Claims (2)

[Claims] 1. A steam exhaust pipe provided in a drainage system of a boiler for discharging steam after introducing steam and drain and centrifuging the steam, and one end opening for preventing steam from flowing out carelessly. Water injection pipe for injecting cooling water into the blowdown tank, using a blowdown tank provided with a siphon-type drain pipe provided by immersing the cooling water downward in the drain, and the cooling water injection pipe A control device for controlling the amount of cooling water injected into the blowdown tank from the blowdown tank. 2. A method of operating a blow-down tank device according to claim 1, wherein cooling water is injected into the blow-down tank before the superheated steam flows into the blow-down tank, so that steam flows out of the drain pipe. A method for operating a blowdown tank device, characterized in that the blowdown tank device is prevented.