JPH02112605A - Adjusting method for condenser in its degree of vacuum - Google Patents

Abstract

PURPOSE:To prevent vibration of a turbine by a high vacuum by providing a small valve, so as to bypass a nozzle inlet valve, halfway an air extraction pipe between a condensor and a gas extraction device, for extracting noncondensable gas in the condenser, and using the small valve performing gas extraction in unsteady time. CONSTITUTION:In a condenser, exhaust steam from a steam turbine 1 is collected into a condenser barrel 2, cooled and condensed by cooling water supplied by a circulating water pump 4. Noncondensable gas in the condenser barrel 2 is successively extracted and released to an exhaust gas processing system 21 by the first and second stage nozzles 11, 12 with drive steam introduced from each steam supply pipes 13, 14. Here, an air extraction bypass pipe 31 of small capacity branches from an air extraction pipe 9 so as to bypass the first stage nozzle inlet valve 10, and the first stage nozzle inlet small valve 32 is provided interposing halfway the pipe 31. When the condenser improves a degree of its vacuum better than the designed degree of vacuum, the small valve 32 is throttled and adjusted so as to obtain the designed degree of vacuum by fully closing the inlet valve 10 and fully opening the small valve 32.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to the operation of a condenser used in a power generation plant,
In particular, the present invention relates to a condenser vacuum adjustment device that is capable of adjusting the condenser vacuum without affecting the environment around the power plant.

[Background of the invention]

FIG. 2 shows a system diagram of the prior art.

Exhaust steam from the turbine 1 driven by steam generated from a steam generator (not shown) is collected in the condenser shell 2,
The circulating water pump 4 exchanges heat with the cooling water sent to the condenser water chamber 3 through the cooling water supply pipe 5 and condenses the water. The degree of vacuum within the condenser body 2 is also ensured by this cooling water.

The cooling water is discharged through a cooling water discharge pipe 7 via a cooling water outlet valve 6.

On the other hand, the non-condensable gas in the condenser shell 2 is
A first stage evaporation supply pipe 13 connected to the stage nozzle 11. Valve 1
Air extraction tube 9. by driving steam supplied through 5. It is sucked through the valve 10 and discharged from the first stage nozzle outlet pipe 17 to the intercooler 19 together with the driving steam, where the driving steam is cooled and becomes condensed water.

The non-condensable gas is again extracted by the second stage nozzle 12 and
Stage steam supply pipe 14. Together with the driving steam supplied through the valve 16, it passes through the second stage nozzle outlet pipe 20, is treated in the exhaust gas treatment system 21, and is then discharged into the atmosphere from the exhaust stack 22.

As shown in Figure 3, the condenser characteristics are as follows: As the cooling water temperature goes from high temperature T1 to low temperature T2, the degree of vacuum in the condenser becomes higher at P2 than Pl, and when the cooling water temperature T1 is the same, the lower the amount of cooling water, the lower the vacuum. It gets worse.

Also, the first stage nozzle 11. As shown in FIG. 4, the characteristics of the second stage nozzle 12 are such that the degree of vacuum in the condenser deteriorates as the amount of extracted non-condensable gas increases.

Furthermore, when non-condensable gas accumulates in the condenser shell 2, the degree of vacuum in the condenser deteriorates as the accumulated gas increases.

The only factor that changes during normal plant operation is the cooling water temperature, which is affected by the outside air temperature.Especially in winter, the cooling water temperature drops and the condenser vacuum level is 10mmHg compared to the design vacuum level.
This results in a high degree of vacuum.

Due to this high degree of vacuum, the rotor inside the turbine 1 (not shown)
There is a possibility of inducing vibration due to instability of the condenser chamber 3 and tube vibration due to high-speed exhaust steam flowing outside the tube (not shown) in the condenser room 3. Adjust the condenser vacuum level and lower it to the design vacuum level. There will be a need to take driving law.

Conventionally, as a method for reducing the degree of vacuum, the first method utilizes the condenser characteristics to reduce the amount of cooling water by restricting the cooling water outlet valve 6, and the first stage nozzle 11. A second method uses the characteristics of the second stage nozzle 12 to slightly open the air suction valve 8 and injects the air into the condenser shell 2 to increase the amount of noncondensable gas; In order to increase the non-condensable gas accumulation in the shell 2, there is a third method of restricting the amount extracted to the first stage nozzle 11 by throttling the first stage nozzle artificial valve]0. Each of the above three methods has the following drawbacks.

(1) In the first method, by reducing the amount of cooling water, the temperature rise of the cooling water becomes larger than the designed value, which has an impact on the environment and does not comply with Keio University and regulatory values.

(2) In the second method, an increase in the amount of noncondensable gas results in an increase in radioactivity released into the atmosphere, especially in the case of an atomic couplant.

(3) In the third method, since the first stage nozzle artificial valve 10 has a large diameter (750A diameter for 1100MWe class), it is necessary to reduce the valve opening to 2 to 3% in order to satisfy the specified function. The above is extremely difficult.

In addition, related to this type of technology.

For example, there is Japanese Patent Publication No. 52-26320.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus which improves the drawbacks of the conventional condenser vacuum adjustment means, such as restrictions on environmental regulations and complication of valve operation, by installing a small bypass valve.

The present invention focuses on the fact that the degree of vacuum in the condenser decreases due to an increase in non-condensable gas within the condenser, and reduces the amount of air extracted to the air extractor. This is because priority was given to simplicity of operation.

[Embodiments of the invention]

FIG. 1 shows a system diagram of the present invention.

The same parts as in FIG. 2 are indicated by the same reference numerals.

An air extraction bypass pipe 31 having a smaller capacity is branched from the air extraction pipe 9, and a first stage nozzle inlet small valve 32 is installed in the middle of the pipe.

The first stage nozzle inlet small valve 32 is provided with an opening gauge 33 for monitoring the opening during throttling operation.

During normal operation, if the condenser vacuum degree is worse than the design vacuum degree, the first stage nozzle inlet valve 10 is opened, the first stage nozzle inlet small valve is closed (or it may be opened), and the condenser corresponding to the cooling water temperature is Operate at vacuum level.

When the condenser vacuum level becomes better than the design vacuum level, the first stage nozzle inlet small valve 32 is fully opened and the first stage nozzle inlet valve 10 is fully closed. In this state, if the condenser vacuum level is higher than the design vacuum level, adjust the first stage nozzle inlet small valve by throttling it so that it reaches the design vacuum level.

With the installation of this small valve 32, the opening of the small valve becomes 50% or more, compared to the throttle opening of 2 to 3% in the first stage nozzle inlet valve 10, making it possible to finely adjust the opening and greatly improving operational convenience. Ru.

Also, the degree of vacuum in the condenser depends on the plant load, and the lower the load, the higher the vacuum, and in this case, it also needs to be adjusted, but if only the first stage nozzle inlet valve 10 is used, it is necessary to keep it fully open. It is almost impossible to deal with it.

The addition of this line overcomes the drawbacks of the prior art.

(1) Environmental regulations due to an increase in cooling water temperature (2) Increase in radioactivity released into the atmosphere (3) Operational restrictions imposed only by the first stage nozzle artificial valve 10 are avoided.

In the future, with the adoption of load-following operation, daily adjustment operation will be required, and the drawbacks of the prior art will be exacerbated.

As a countermeasure for today's load following operation, it is also possible to detect the condenser vacuum level and input operation signals to the first-stage nozzle population valve 10 and the first-stage nozzle inlet small valve 32 to automatically adjust the operation.

〔Effect of the invention〕

The present invention has the following effects.

1. The degree of vacuum in the condenser can be easily adjusted, and the high degree of vacuum allows operation to prevent turbine vibration and condenser tube vibration.

2. It is easy to operate and can automatically adjust the vacuum level of the condenser.

[Brief explanation of drawings]

FIG. 1 is a system diagram of an embodiment of the present invention, FIG. 2 is a system diagram of the prior art, FIG. 3 is a characteristic diagram of a condenser, and FIG. 4 is a characteristic diagram of an air extraction device. 1... Turbine, 2... Condenser body, 3... Condenser ice chamber, 4... Circulating water pump, 5... Cooling water supply pipe,
6... Cooling water outlet valve, 19... Intercooler, 2
o... 2nd stage early ■ 4 phantom K amount ('/-) early #3 blood f coagulation ≧ main force - K amount (%)

Claims (1)

[Claims] 1. A condenser that cools the exhaust gas of the turbine driven by the steam generated by the steam generator of the power plant and maintains the degree of vacuum. A condenser is connected to the condenser to remove non-condensable gas in the condenser. It includes a gas extraction device to extract, a large valve for normal operation installed between the gas extraction device and the condenser, and a small valve to bypass it, and the vacuum level inside the condenser is steady during continuous plant operation. A condenser vacuum adjustment device that extracts gas using a large valve at times and a small valve at unsteady times.