JPS61110877A - Vacuum pump for condenser - Google Patents

Abstract

PURPOSE:To increase holding capacity and to realize high vacuum operation of a condenser, by providing a steam ejector and a steam condenser to a water sealed rotary vacuum pump as a vacuum ejector for a condenser. CONSTITUTION:A steam ejector bypass valve 10 is closed, and driving steam is fed to a steam ejector 4 provided on the upstream side of a water sealed rotary vacuum pump 11, passing through a driving steam pipe 9, via a driving steam check valve 8 and a pressure reducing valve 17. The steam ejector 4 is operated by the steam to vacuumize the inside of a condenser up to the rated vacuum of it. Further, gas in the condenser 1 is sucked by the suction effect of a steam ejector 4. The driving steam and the sucked gas are mixed with each other, flowing into a steam condenser 5, exchanging heat with cooling water 6 at the inlet of a steam condenser, being condensed, and is discharged to a separator tank 12 by the water sealed rotary vacuum pump 11. With such an arrangement, holding capacity is increased by the steam ejector, and the capacity of a condenser can be increased without changing the water sealed rotary vacuum pump. Accordingly, high vacuum operation of a condenser can be taken place, suppressing the decrease of plant efficiency at the minimum possible.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a condenser vacuum pump device comprising a water ring rotary vacuum pump and a steam ejector, as an air extraction device for a steam turbine power generation equipment having a condenser. Regarding. .

[Background of the Invention] Conventionally, a device that combines a water seal rotary vacuum pump and an air ejector has been widely used as an air extraction device for steam turbine power generation equipment with a condenser.
Up to mHg vac, the water ring rotary vacuum pump is operated alone, and in order to further increase the vacuum, the air ejector is placed in the first stage and the water ring rotary vacuum pump is used in the second stage, and the vacuum is increased to the condenser rated vacuum. raise. (Hogging operation,
The method of interlocking the pneumatic ejectors is called holding operation. ) In this case, atmospheric air is used as the driving fluid for the air ejector.

Also, normally, two condenser vacuum pump devices are installed in one condenser, and when the condenser vacuum is raised at the time of plant start-up, two pumps are operated to complete the vacuum raise in order to raise the vacuum in succession. rear,
During normal plant operation, one unit is in operation, and the remaining unit is on standby. If the amount of air leakage is abnormally large or the vacuum in the condenser cannot be maintained, the standby unit will automatically start operating. It is known. (Thermal and nuclear power generation magazine Vot
.

26ya 11. November 1975 9 pages 1264-1267
) However, pneumatic ejectors tend to have limitations in improving condenser deaeration performance or increasing holding capacity for high-vacuum operation of the condenser, and by replacing them with steam-type ejectors, pump Capacity can be increased without changing the main unit.

[Purpose of the invention]

The purpose of the present invention is to combine a water ring rotary vacuum pump and a steam ejector as an air extraction device for a condenser, thereby minimizing a drop in plant efficiency, increasing holding capacity, and enabling high vacuum operation of the condenser. An object of the present invention is to provide a condenser vacuum pump device that does the following.

[Summary of the invention]

The degree of vacuum in the condenser is determined by three factors: the performance of the condenser itself, the capacity of the air extraction device, and the amount of air leaking into the condenser (including non-condensable gas from turbine exhaust, etc.). . Here, if the capacity of the air extraction device is sufficiently larger than the amount of air leakage, the vacuum of the condenser body is determined only by the condenser heat load and the conditions on the cooling water side, and this is the attainable degree of vacuum. Become.

When the turbine is operated under high load and the condenser cooling water temperature is high, the condenser vacuum level is low (high pressure),
On the other hand, when the turbine is operated at a low load and the condenser cooling water is low, the condenser vacuum degree becomes high (low pressure). However, the capacity of the condenser vacuum pump has the characteristic that it decreases as the suction vacuum increases to high vacuum (low pressure), so even if the amount of leaked air is constant, the suction vacuum is high (low pressure). As the air extraction capacity becomes insufficient or the extraction capacity becomes zero, the vacuum level of the condenser becomes equal to the capacity of the condenser vacuum pump, or the backup machine is started and two units are operated. It is necessary to

By adopting a steam ejector and combining it with a water ring rotary vacuum pump, it is possible to increase the holding capacity and air extraction capacity.
The performance of the condenser vacuum pump that matches the condenser vacuum degree can be maximized, making it possible to operate the plant with high efficiency.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 shows that when air is extracted from the condenser 1 by the condenser vacuum pump device, first, when the vacuum rises, the air extracted from the condenser 1 by the water seal rotary vacuum pump 11 is extracted. It passes through the condenser vacuum pump artificial valve 3t through the pipe 2, bypasses the steam ejector 4, and is discharged to the atmosphere from the steam ejector bypass valve 1otAb and the separator tank 12. On the other hand, since this pump is a water-sealed water pump, the pressure of the sealed water stored in the separator tank 12 is increased by the water-sealed pump 13 and is supplied to the water-sealed rotary vacuum pump 11 via the water-sealed cooler 14. , and is discharged to the separator tank 12 together with the extracted air from the condenser. In the separator 12, extracted air and sealed water are separated, and the air is discharged to the atmosphere, drained, and sent to a sealed water pump for reuse.

In addition, when the water seal is supplied to the water seal rotary vacuum pump 11, heat is generated corresponding to the efficiency loss of the water seal rotary vacuum pump, and the heat is recovered by the water seal, and the temperature of the seal water increases. , and are cooled by heat exchange in the sealed water cooler 14. The water seal cooler inlet cooling water 15 is normally supplied from the bearing cooling water system of the plant, and the water seal cooler outlet cooling water 16 is recovered to the bearing cooling water system again. When the vacuum in the condenser is increased by this method, the water seal rotary vacuum tube 11 alone has its limits, and can only raise the vacuum to near the saturation pressure of the seal water. For this reason, normally 660mmHg
Vac, the steam type ejector bypass valve 10 is changed, and the driven steam stop valve 8,
Drive steam is supplied through the pressure reducing valve 17 and the steam ejector 4
are linked to raise the vacuum to the rated vacuum of the condenser.

Here, as a driving steam source for the steam type ejector, auxiliary steam from another can or zero can, or exhaust or extracted steam from a steam turbine is used. In addition, the steam type ejector driving steam pipe 9 includes a pressure reducing valve 17 as an example of a steam pressure reducing device.
is provided, but an orifice may also be used. The purpose of installing this pressure reducing device is to reduce the pressure of the driving steam, thereby increasing the volumetric flow rate of steam and reducing the amount of driving steam for the steam ejector 4. Examples include supplying steam.

Furthermore, the gas in the condenser 1 is sucked through the suction port of the steam ejector 4, and the driving steam and this suction gas are mixed.
It flows into the steam condenser 5, exchanges heat with the steam condenser inlet cooling water 6, is condensed, and is discharged to the separator tank 12 by the water ring rotary vacuum pump 11. Here, the steam condenser inlet cooling water 6 is normally supplied to the bearing cooling water system of the plant, and the steam condenser outlet cooling water 7 is recovered to the bearing cooling water system again.

FIG. 2 shows another embodiment of the present invention, which differs from FIG. The condensate water is supplied to the steam condenser 5 through the steam condenser inlet cooling water 21, and the steam condenser outlet cooling water 22 is returned to the grand condenser 20 at the condensate pump outlet and to the downstream condenser 1B. Here, the cooling water of the steam condenser is parallel to the cooling water (condensate) of the grand condenser 20, but the condensate pipe 1 on the upstream side or downstream side of the grand condenser 20
8 to the cooling water (condensate) of the ground condenser 20 may be connected in series.

In this embodiment, the amount of heat of the driving steam of the steam ejector 4 can be recovered to the condensate system at the condenser outlet.

〔Effect of the invention〕

According to the present invention, the holding capacity is increased by the steam ejector, and the capacity can be increased without changing the water ring rotary vacuum pump body, and the high vacuum operation of the condenser minimizes the decline in plant efficiency. It is possible to reduce the

[Brief explanation of the drawing]

1 and 2 are schematic system diagrams of a condenser vacuum pump according to the present invention.

Claims (1)

[Scope of Claims] 1. In a steam turbine power generation facility equipped with a condenser that cools and condenses steam turbine exhaust, a water ring rotary vacuum pump is equipped with a steam ejector and a steam ejector as an air extraction device for the condenser. A condenser vacuum pump device characterized by being equipped with a condenser. 2. In claim 1, a pressure reducing device is installed in the drive steam system of the steam ejector,
A condenser vacuum pump device that reduces and adjusts the inlet steam pressure of the steam ejector. 3. In claim 1, the cooling water of the steam condenser is taken from the outlet condensation system of the condenser and returned to the condensation system again through the steam condenser. A condenser vacuum pump device characterized by recovering heat from driving steam.