JPH049280B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an exhaust gas treatment device that heat-treats exhaust gas generated in a boiling water nuclear power plant.

[Technical background of the invention and its problems] In a boiling water nuclear power plant, reactor steam generated in a nuclear reactor is guided to a turbine through a main steam pipe, and this turbine drives a generator to generate electricity. I'm going. The steam used in the turbine is returned to the main condenser, but air, water radiolysis gas (oxygen, hydrogen ), activated gas from reactor water, nuclear fission product gas, etc. are mixed in, and these gases from the main condenser (hereinafter referred to as "exhaust gas") are treated by an exhaust gas treatment device.

The exhaust gas treatment device consists of an air extractor that extracts exhaust gas from within the main condenser, an exhaust gas preheater that heats the exhaust gas extracted by the air extractor to a predetermined temperature, and an exhaust gas that has been heated to this predetermined temperature. It consists of an exhaust gas recombiner that recombines hydrogen and oxygen, and an exhaust gas condenser and filter that cool and condense the recombined exhaust gas.

In an exhaust gas treatment apparatus having such a configuration, steam from an in-house boiler (hereinafter referred to as "HS") has conventionally been used as a heating source for the exhaust gas preheater.

FIG. 1 is a diagram showing a heating system of a conventional exhaust gas preheater. The exhaust gas flowing into the exhaust gas preheater 12 from the exhaust gas supply conduit 11 is heated in the exhaust gas preheater 12 and then flows through the exhaust gas discharge conduit 13 to the downstream exhaust gas recombiner. On the other hand, the steam for heating the exhaust gas preheater 12 is supplied to the HS supply conduit 15 from the HS supply equipment 14 equipped with an in-house boiler.
The exhaust gas is supplied to the exhaust gas preheater 12 via the . A temperature control valve 16 is installed in the HS supply conduit 15 so that the amount of steam supplied to the exhaust gas preheater 12 is adjusted based on the temperature output signal 18 from the temperature detector 17 installed in the exhaust gas discharge conduit 13. It's summery. In addition, the HS that supplied heat to the exhaust gas preheater 12 is
After that, it passes through the HS recovery conduit 19 to the HS supply equipment 14.
will be collected.

However, in exhaust gas treatment equipment that uses HS as a heating source for such an exhaust gas preheater,
Since the exhaust gas treatment system is directly connected to the operation of the nuclear power plant, it is necessary to secure a heating steam source for backup in consideration of reliability, and a plurality of HS supply facilities 14 are installed. Additionally, in the summer, HS is used only as an exhaust gas preheater, but the amount of steam required to heat the exhaust gas preheater is low (approximately 0.3 tons/hour), and for this reason, approximately 12 tons/hour.
It is extremely uneconomical to operate an in-house boiler that has a steam supply capacity of 300 mph in terms of equipment costs, maintenance costs, and maintenance inspections.

Therefore, a device using the main steam line (MS line) in addition to the in-house steam line (HS line) as a heating source for the exhaust gas preheater has been developed (Patent Application No. 215411 of 1982); In the device,
For the steam supply line for heating the exhaust gas preheater connected to one exhaust gas preheater, the HS line and
Since the MS lines are connected respectively, the HS
When switching between line and MS line operation, there is a risk that some of the steam from the MS line will mix into the HS line, contaminating the HS line with radioactive steam.

[Purpose of the invention]

The present invention has been made with these points in mind, and by multiplexing the heating sources of the exhaust gas preheater, it aims to improve reliability and save energy, and the HS line is connected to the main steam of the MS line. It is an object of the present invention to provide an exhaust gas treatment device that is not contaminated by.

[Summary of the invention]

The present invention is an exhaust gas treatment device for a nuclear power plant equipped with an exhaust gas preheater that heats exhaust gas extracted by an air extractor from a main condenser to a predetermined temperature before sending it to an exhaust gas recombiner. , the exhaust gas preheater uses in-house steam as a heating source;
The main steam is separated from the exhaust gas preheater using the heat source via a separation switching valve, and the in-house steam line for exhaust gas heating and the main steam line for exhaust gas heating are connected to each exhaust gas preheater. It is said that

According to the present invention, the exhaust gas preheater and the steam line for heating the exhaust gas preheater are completely separated and independent for in-house steam and main steam, so that the steam in the main steam line does not mix into the in-house steam line. , contamination of in-house steam lines is prevented.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 2 and 3.

FIG. 2 is a system diagram showing an example of the exhaust gas treatment apparatus according to the present invention, and FIG. 3 is a diagram showing the heating steam line near the exhaust gas preheater in more detail.

In FIG. 2, reference numeral 21 is a main condenser, and the exhaust gas in the main condenser 21 is extracted by an air extractor 22 connected to the main condenser 21. The air extractor 22 includes first stage ejectors 23a, 23b and second stage ejectors 25a, 2 which are operated by main steam (hereinafter referred to as "MS").
5b, and 1 operated by HS (house steam)
A stage ejector 24 and a second stage ejector 26 are provided. Ejector 23a, 23 operated by MS
b, 25a, 25b and the ejectors 24, 26 operated by the HS are arranged in a parallel relationship with each other and separated from each other in an independent relationship via a separation valve. In addition, the first stage ejectors 23a, 23b, 2
An ita capacitor 27 is disposed between the ejector 4 and the second stage ejectors 25a, 25b, and 26. An MS supply conduit 28 is connected to each of the ejectors 23a, 23b, 25a, and 25b via an MS supply branch conduit 31, so that MS for operating the ejectors is supplied. In addition, MS supply conduit 2
8, an MS pressure control valve 29 is disposed in the middle. On the other hand, an HS supply facility 33 is connected to the ejectors 24 and 26 via an HS supply conduit 32, so that HS for operating the ejectors is supplied.

On the downstream side of the air extractor 22, an exhaust gas preheater 3 whose heating source is an MS is installed via the exhaust gas supply conduit 11.
4 and an exhaust gas preheater 36 using HS as a heating source,
They are arranged and connected in parallel to each other, and are separated from each other in an independent relationship by separation switching valves 35a and 35b, which are respectively disposed on the inlet side. An MS supply branch conduit 37 is connected to the exhaust gas preheater 34 that uses MS as a heating source.
The MS supply conduit 28 is connected through the HS supply conduit 38, and the HS supply equipment 33 is connected through the HS supply conduit 38 to the exhaust gas preheater 36 which uses HS as a heating source.

FIG. 3 is an enlarged view showing the steam piping around the exhaust gas preheater. As shown in the figure, the MS supply branch conduit 37 and the HS supply conduit 38 are provided with an MS isolation valve 39 and an HS isolation valve 41, respectively. Further, a pressure detector 43 is provided in the MS supply conduit 28 . This pressure detector 43
MS pressure control valve 29, separation switching valve 35a, 3
5b, the MS isolation valve 39, and the HS isolation valve 41 through signal lines, and the detected MS pressure signal 43a is sent to each valve to control opening and closing operations. Further, an exhaust gas discharge conduit 44 connected to the exhaust gas preheaters 34, 36,
Temperature detectors 45 and 47 are disposed at 46, respectively, and the detected exhaust gas temperature signals 45a and 47a
MS supply branch conduit 37, HS supply conduit 3
The opening and closing operations of temperature control valves 48 and 49 disposed at 8 can be controlled. Also,
Steam recovery conduits 51, 53 are connected to the exhaust gas preheaters 34, 36, respectively, and drain traps 52, 54 are disposed in the respective steam recovery conduits 51, 53.

In addition, in this example, the HS line and MS
Cross contamination with lines (cross
To prevent contamination, it is desirable to provide a check valve on the HS line side and to arrange multiple valves in series. Furthermore, it is desirable to keep the HS supply pressure higher than the MS supply pressure.

On the downstream side of the exhaust gas preheaters 34 and 36, exhaust gas recombiners 55 and 57 and exhaust gas condensers 56 and 58 are successively connected, respectively, and an activated carbon hold-up device 59 and an exhaust stack 60 are also connected.

Next, the operation of this embodiment having such a configuration will be explained.

The exhaust gas in the main condenser 21 is extracted by an air extractor 22 and sent via the exhaust gas supply conduit 11 to the exhaust gas preheater. The selection of which exhaust gas preheater to use for heating is determined based on the MS pressure signal 43a from the pressure detector 43 disposed in the MS supply conduit 28.

The operation of the exhaust gas treatment device in each operation mode will be described below.

(a) At startup Since MS is not supplied, the exhaust gas preheater 36 is operated using HS as a heating source. That is, based on the MS pressure signal 43a from the pressure detector 43, the separation switching valve 35a and the MS isolation valve 39 are closed, and then the separation switching valve 35b and the HS isolation valve 41 are opened. supply mode). HS is supplied from the HS supply facility 33 to the exhaust gas preheater 36 and the ejectors 24, 26 via the HS supply conduits 32, 38. Ejector 24, 2
6, the exhaust gas is extracted, supplied to the exhaust gas preheater 36, heated by the HS, and sent to the exhaust gas recombiner 57. The supply amount of HS is controlled by a temperature control valve 49.

(b) Normal operation Since MS is supplied during normal operation, the exhaust gas preheater 34 is operated using the MS as a heating source. That is, when the MS pressure detected by the pressure detector 43 exceeds a predetermined value, the MS pressure signal 43a
As a result, the separation switching valve 35b and the HS isolation valve 41 on the HS line side are closed, and subsequently the separation switching valve 35a and the MS isolation valve 39 on the MS line side are opened. Thereby, MS for heating is supplied to the exhaust gas preheater 34. MS simultaneously ejectors 23a, 23b,
The exhaust gas is also sent to 25a and 25b, extracts the exhaust gas, and sends the exhaust gas to the exhaust gas preheater 34. The amount of MS supplied to the exhaust gas preheater 34 is determined by the MS pressure control valve 2.
9. Controlled by opening and closing the temperature control valve 48.

(c) At the time of operation stop and MS supply stop Since MS is not supplied, the exhaust gas preheater 36 is operated using HS as a heating source. The steam supply mode is the same as (a) at startup.

In addition, regarding the operation of this embodiment, there are also the following:
For example, in winter, HS may be used as a heating source along with MS during normal operation. Also, M.S.
Instead of controlling the operation of the air extractor 22 and the exhaust gas preheater in conjunction with each other using the pressure signal 43a, the exhaust gas preheater may be selectively used manually at the discretion of the staff.

〔Effect of the invention〕

As explained above, according to the present invention, the HS and MS are used together as a heating source for the exhaust gas preheater, and each is configured as an independent supply line, so that the reliability of the exhaust gas treatment device is improved, and Cross contamination between the HS line and MS line can be completely prevented. Furthermore, there is no need for low-load operation of the in-house boiler in the summer, so there is a great economic effect. In addition, operation can be controlled using MS pressure signals, improving operability during startup and stopping, and preventing erroneous operations. Furthermore, by enabling manual operation, it is possible to respond to driving conditions.

Note that the present invention can be additionally installed in an existing exhaust gas treatment device without major changes.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing a heating method of a conventional exhaust gas preheater, Fig. 2 is a system diagram showing an exhaust gas treatment device according to the present invention, and Fig. 3 is a diagram showing a steam piping path around the exhaust gas preheater according to the present invention. It is a system diagram. 21... Main condenser, 22... Air extractor, 28...
MS supply conduit, 33...HS supply equipment, 34, 36
...Exhaust gas preheater, 35a, 35b...Separation switching valve,
38...HS supply conduit, 55, 57...exhaust gas recombiner.

Claims (1)

[Claims] 1. In an exhaust gas treatment device for a nuclear power plant equipped with an exhaust gas preheater that heats exhaust gas extracted by an air extractor from a main condenser to a predetermined temperature before sending it to an exhaust gas recombiner, The exhaust gas preheater is separated into an exhaust gas preheater that uses in-house steam as a heating source and an exhaust gas preheater that uses main steam as a heating source via a separation switching valve. An exhaust gas treatment device characterized in that an in-house steam line and a main steam line for heating exhaust gas are connected. 2. The exhaust gas treatment device according to claim 1, wherein the separation switching valve is switched and controlled according to the main steam supply pressure.