JPS60232490A - Condensating system - Google Patents

Abstract

PURPOSE:To contrive reduction of the maximum utility pressure of a condensating system by reducing a full lift of a condensate pump, by providing an air extractor and a water feeding system for a gland steam condenser by branching from a condensating system. CONSTITUTION:Condensate discharged from a condensate pump 4 performs water feeding to an air ejector and a gland steam condenser 9 by providing a small diameter branch condensate pipe 15 which is once ramified from a main flow of condensate piping 15 and providing further a small capacity pump 16 after impurities of the condensate have been removed by a filter 5 of the condensate and a desalting device 6 of the condensate. To make a quantity of feeding water constant a flow meter 17, a liquid quantity adjusting device 18 and an adjusting valve 19 are provided additionally. With this piping application, the full lift of a condensate pump is reduced, and it becomes possible that the maximum utility pressure of a delivery line of the condensate pump is made to fall within a range of under 20kg/cm<2>g, water chambers of the air ejector and the gland steam condenser become fed to only a required quantity of water and the diameters of the water chamber and the condensate pipe are reduced.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a condensate system of a power generation plant, and in particular, the present invention relates to a condensate system for a power generation plant, and in particular, to reduce the total head of a condensate pump under conditions where an air extractor or a gland steam condenser is installed. The present invention relates to a condensate system suitable for reducing the maximum operating pressure of the condensate system.

[Background of the invention]

An example of a conventional nuclear power plant will be explained with reference to FIG.

The steam generated in the nuclear reactor 1 performs work through expansion in the turbine 2, and then condenses in the condenser 3 to become condensed water. Condensate is sucked out by a condensate pump 4, impurities are removed by a condensate desalination device 5 and a condensate desalination device 6, and then passed through a condensate pipe 7 to an air extractor 8 and a grand steam condenser 9. After cooling, the pressure is increased by the condensate boost pump 10, and the temperature is raised by the feed water heater 11.
A closed circuit is formed in which the pressure is increased by the water supply pump 12 and then returned to the reactor 1 via the water supply pipe 13. The air extractor 5 and the grand steam condenser 6 normally continue to operate in order to maintain the vacuum in the condenser 3 not only during load operation but also during no-load operation during the start-stop process. is the condensate re-m ring valve 14
is opened and the condensate recirculating operation returns to the condenser 3 to ensure a minimum flow rate of the air extractor 8 and the grand steam condenser 9.

The amount of cooling water required to ensure the functions of the air extractor 8 and the gland steam condenser 9 is approximately 500T/W for the 800 MWe class.
h, but the total amount of 800 MWe class condensate is about 5000 T.
/h, the excess water is passed through an orifice in the water chamber, thereby bypassing the cooling pipe.

The first problem with the prior art is that the air extractor 8 and the gland steam condenser 9 have a large water head loss of approximately 10 m in total despite the small amount of water required, and as a result, the total head of the condensate pump 4 is reduced. It is about 150m, and the auxiliary power of the condensate pump motor is 8.
In the case of 00MWe class, the total power of the two units is about 3000KW, which is large.

The second is that the maximum working pressure of the discharge line of condensate pump 4 is 20
kg/a1g, welding inspection of discharge line equipment, piping, and valves is required, which increases costs.

As a measure to prevent the current from exceeding 20 kg/cIITg, recent plants have changed the characteristics of the condensate pump 4 from the conventional characteristics (solid line) to the total head between specification point A and cut-off point B, as shown by the dashed line in Figure 2. In order to keep the ratio (slope) H11/HA lower than before, and to suppress manufacturing variations in the cut-off total head HII, we developed models.
After manufacturing, measures such as trimming are taken to keep the condensate pump 4 within specified values, but this results in an increase in the cost of the condensate pump 4 itself.

The third problem is the air extractor 8 and the gland steam condenser 9.
Although the amount of water required is small, the ice chamber is designed to be oversized in order to pass the entire amount of condensate.

The fourth problem is that the air extractor 8 and the ground steam condenser 9 are configured with the condensate pump 4, condensate filtration and desalination device 8, and condensate supersalt device! It is generally installed at a floor height higher than 9, and the 800 MW e-class large-diameter condensate pipe with a diameter of approximately 700 km meandering up and down the building floors, making it difficult to increase the piping space in the building. impact, and piping costs have also become an issue.

[Purpose of the invention]

The object of the invention is to provide a system that makes it possible to solve the problems of the prior art.

[Embodiments of the invention]

An embodiment of the present invention will be explained with reference to FIG.

After removing impurities from the condensate discharged from the condensate pump 4 through a condensate filtration device 5 and a condensate desalination device 6, a small-diameter branch condensate pipe 15 is provided which branches off from the main stream of the condensate pipe 7. Furthermore, a small capacity pump 16 is provided to supply water to the air extractor 8 and the gland steam condenser 9. In order to keep the amount of water flowing constant, a flow meter 17, a liquid amount regulator 18, and a regulating valve 19 are additionally installed. The specifications of each equipment in this configuration are that the pump capacity is approximately 500 T/h, the total head is approximately 15 m, and the diameter of the condensate pipe is approximately 200 m. Furthermore, the weight of the ice chambers of the air extractor 8 and the grand steam condenser 9 is also reduced in accordance with the required capacity of about 500 T/h.

Another embodiment will be explained with reference to FIG. In order to reduce the head loss at the flow meter 17 shown in FIG. 3, a differential pressure regulator 20 is provided to keep the differential pressure between the air extractor 8 and the grand steam condenser 9 constant when approximately 500 T/h of water flows. , controls the opening degree of the regulating valve 19.

Moreover, in FIG. 5, the air extractor 8 and the gland steam condenser 9 are installed in parallel, whereas in FIG. 4, the air extractor 8 and the gland steam condenser 9 are installed in series.

There is also a configuration in which the air extractor 8 and the ground air condenser 9 shown in FIG. 3 are arranged in parallel.

〔Effect of the invention〕

According to the present invention, (1) The total head of the condensate pump is reduced by approximately 10 m (dashed line in Figure 2), and the shaft power of the condensate pump drive motor is reduced to 800 m.
For MWe class, the reduction is approximately 200 KW. On the other hand, the shaft power of a small capacity pump is as small as about 29KW. Therefore, the total reduction in shaft power is approximately 180KW.

(2) The maximum working pressure of the condensate pump discharge line is 20 kg.
/a1g, which reduces the manufacturing cost of the condensate pump.

(3) Only the required amount of water is passed through the ice chambers of the air extractor and grand steam condenser, resulting in a significant reduction in the ice chamber size.

(4) The condensate pipe diameter around the air extractor and grand steam condenser is reduced from 70'Om to 200'Om for 800MWe class.

[Brief explanation of the drawing]

Figure 1 is a schematic system diagram of a conventional power generation plant, and Figure 2 is a characteristic diagram of flow rate and total head in a condensate pump. FIG. 3 is a system diagram around an air extractor and a grand steam condenser according to the present invention, and FIGS. 4 and 5 are system diagrams around an air extractor and a grand steam condenser according to other embodiments of the present invention. It is. 4... Condensate pump, 5... Condensate filtration device, 6...
Condensate desalination device, 7... Condensate pipe, 8... Air extractor,
9... Grand steam condenser, 10... Condensate boost pump, 15... Branch condensate pipe, 16... Pump, 17.
...Flowmeter, 19th l 12th // 3rd port

Claims (1)

[Claims] 1. A condenser that condenses steam from a steam turbine, and extracts cracked gas from the nuclear reactor and air leaking from the atmosphere through the condenser, and cleans the inside of the condenser. an air extractor to create a vacuum;
A grand seal steam condenser of the steam turbine, a condensate pump that sucks out and pumps condensate condensed in the condenser, and a condensate pipe that guides the condensate pump discharge water to a condensate boost pump on the downstream side. In a condensate system in a power generation plant comprising: A separate route of piping is provided that once branches from the condensate pipe and returns to the condensate pipe at the inlet of the condensate boost pump. A condensation system in a power generation plant, characterized in that a pump and a valve are provided on the branch line, and the air extractor and the gland seal steam condenser are installed.