JPS5851195B2 - condensate equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a condensation system for thermal power and nuclear power plants, and in particular, condensed water condensed in a condenser is temporarily transferred to a condenser installed separately from the condenser. The present invention relates to an improvement in a condensing device in which purified condensate is passed through a water purifying device, returned to the condenser again, and then sent to a boiler or a steam generator.

Technical background of the invention and its problems Generally, in thermal and nuclear power plants, boilers,
The condensate extracted from the hot well of the condenser is purified through a condensate purification device so that the feed water sent to the steam generator meets predetermined water quality standards.

This condensate purification device is used by being incorporated into the condensate system of the turbine cycle, but in this case, the flow rate of condensate flowing through the condensate purification device changes as the plant output fluctuates.
There are concerns about an overall decline in water quality due to the purification capacity of condensate purification equipment.

Particularly in nuclear power plants, if the quality of the water supplied to the steam generator deteriorates, the amount of radioactive substances increases, making the problem even more serious.

In recent years, the technology shown in Figure 1 has been proposed as a technology to solve these problems, and there is an opportunity for this technology to be adopted in Japan's most advanced nuclear power plants.

This technology will be explained below with reference to the drawings. The exhaust gas of the turbine 1 is condensed in the condenser 2, becomes condensate, and the first
The water is collected in hot well 3.

Subsequently, the condensate is passed from the first hot well 3 to the circulation pump 4.
is extracted through the condensate purifiers 5 and 6,
Here, condensate is supplied to the condensate purifiers 5 and 6 in an amount corresponding to the capacity of the condensate purifiers 5 and 6, and the water quality is adjusted over a necessary period of time.

The condensate then passes through the heat exchanger T to the second hot well 9.
The water is recovered from there and sent to a boiler or steam generator (not shown) by a condensate pump 10.

In this configuration in which the condensate purification devices 5 and 6 are made independent from the condensate system of the turbine cycle, it is possible to maintain the condensate flow rate constant regardless of output fluctuations of the power plant, and the condensate purification device You can maximize the abilities of 5 and 6.

However, while this technology greatly contributes to improving the quality of condensate, it has the following problems that impede the sound operation and management of power plants.

That is, the condenser 2 in which the above-mentioned system is installed usually has 70
It is a vacuum container maintained at a high vacuum of 0 imHg or more,
The system internal pressure in the portion connected to the condenser 2 is in a negative pressure state close to the above level.

Therefore, in order to smoothly recover the condensate flowing out from the first hot well 3 to the second hot well 9, it is necessary to reduce the system pressure to the condensate in the path after the heat exchanger 7 where the condensate is heated. It is necessary to suppress the evaporation of some of the condensate by maintaining the pressure above the saturation pressure, but as mentioned above, there are parts of the system that are under negative pressure.

Therefore, in order to maintain the pressure level of the system above a certain level, that is, above the saturation pressure of condensate, a pressure regulating valve 8 is provided in front of the inlet of the second hot well 9 as shown in FIG. The first consideration is to control the

However, it is very dangerous to easily apply such control technology to highly automated thermal power and nuclear power plants.

As an example, let us discuss the inconvenience when the circulation pump 4 in the system stops abnormally and the backup pump automatically starts.
When the system pressure suddenly decreases due to the stoppage of the circulation pump 4, this pressure change propagates through the system at the speed of sound, whereas the response of the pressure regulating valve 8 is relatively slow, so the valve opening is A large amount of bubbles will be generated until the position is set to suppress the pressure drop.

Now, if the standby pump starts automatically,
As the system pressure returns to its normal value, the bubbles generated at this time further increase the volume, causing the condensate that can no longer be accommodated in the system to violently collide with piping and equipment, resulting in so-called water hammer. exhibit a phenomenon.

This water hammer phenomenon not only damages and destroys the equipment that makes up the system, but also poses a risk of human injury if problems such as internal fluid leakage occur.

In this way, the method of controlling the system pressure using the pressure regulating valve 8 is not necessarily a good idea, and even if this technology could be further advanced, the above-mentioned concerns would not be completely resolved. It is something that will not disappear.

Therefore, the next idea is to install all the equipment that makes up the system at a position lower than the water levels a and b of the first hot well 3 and second hot well 9 of the condenser 2, and A method that uses the head to maintain the internal pressure above a certain level is attracting attention.

Since this method utilizes gravity, there are no inconveniences resulting from the problem of time delay in control as described above, and it is sufficiently reliable.

However, if this method is adopted, the construction cost of the turbine building of the power plant will inevitably increase significantly.

That is, the condenser 2 is normally installed in the basement of the turbine building for reasons such as equipment arrangement.

Here, the first hot well 3 and the second hot well 9 formed at the bottom of the condenser 2 are naturally located near the floor of the underground section, and their water levels a and b are also below the floor. It is set at a slightly higher location.

In the above-mentioned method, each device such as the condensate purification devices 5 and 6 is placed with the necessary hydrostatic head secured at a position lower than the water levels a and b, so these devices are further installed under the underground. A housing section must be provided, and the increase in turbine building space significantly increases the construction cost of the power plant.

Thus, the concept of making the condensate purification devices 5 and 6 independent from the condensate system of the turbine cycle also has problems in practical terms, and its realization is in doubt.

OBJECT OF THE INVENTION The object of the present invention is to provide a condensate device that constantly applies constant pressure to a system equipped with a condensate purification device, thereby making it possible to smoothly convey condensate. .

Summary of the Invention The present invention has first and second hot wells partitioned at the bottom of the condenser, and condensate stored in the first hot well is passed through a condensate purification device to the second hot well. In the condensate device configured to supply water to the hot well, a condensate reservoir is provided in a route leading from the condensate purification device to the second hot well,
The top of the condensate reservoir and the condenser are communicated with each other via a balance pipe.

Examples of the invention Hereinafter, one embodiment of the present invention will be described with reference to FIG. 2.

Note that in FIG. 2, parts given the same reference numerals as those shown in FIG. 1 are equivalent to those shown in FIG. 1, so a description of this point will be omitted to avoid duplication.

In FIG. 2, the first hot well 3 and the second hot well 9 are formed at the bottom of the condenser 2, which is similar to the conventional one. Vessel 2
A condensate reservoir 11 is provided near the.

This condensate reservoir 11 is connected in the upper part to the heat exchanger 7, while in the lower part it communicates with the second hot well 9 of the condenser 2.

Here, the inlet 13 of the condensate reservoir 11 is set at a height such that the pressure within the system is always equal to or higher than the saturation pressure of condensate, taking into account transient operating conditions.

In other words, the inlet 13 is provided at a position somewhat higher than the devices that make up the system.

Further, the condensate reservoir 11 is communicated with the condenser 2 via a balance pipe 12.

Since the condensation device according to the present invention is configured as described above, the condensate reservoir 11 communicating with the condenser 2 via the balance pipe 12 is equivalent to the condenser 2 throughout the operation of the power plant. The pressure level is maintained at a high vacuum of 700 yrrtHg or higher.

During this time, pressure due to static water head is always applied to each point in the system in proportion to the distance from the inlet 13 of the condensate reservoir 11, and the pressure level at each point is higher than that of the condensate reservoir 11.

Therefore, not only during normal operation, but also when the system pressure suddenly drops due to an abnormal stop of the circulation pump 4, etc., the system pressure can be maintained above the saturation pressure of condensate. Outflowing condensate can be smoothly collected into the second hot well 9 via the condensate reservoir 11.

Effects of the Invention The advantage of the present invention is that no pressure control means such as valves are used when applying pressure to the system equipped with the condensate purification devices 5 and 6, so there are no delays in control time or malfunctions in control operation. This means that inconveniences derived from the problem, such as the water hammer phenomenon described in FIG. 1, do not occur at all, and this greatly contributes to the sound operation and management of the power plant.

In addition, the equipment that makes up the system is the inlet 13 of the condensate reservoir 11.
Although there is a restriction that these devices be placed lower than the first hot well 3 and the second hot well 9, there is no problem in installing these devices above the first hot well 3 and the second hot well 9, and the turbine building can be constructed. In addition, it is sufficient to secure the same amount of building space as before.

As is clear from the above description, the present invention is designed to maintain a constant pressure at all times in a system that supplies condensate of a power plant, which is equipped with a condensate purification device that is added to improve the water quality of the condensate. Since the condensate can be added and the condensate can be smoothly transported, it has excellent effects such as facilitating operation management of the power plant.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an example of a technique that was studied prior to the present invention, and FIG. 2 is a system diagram showing an example of a condensing device according to the present invention. 2... Condenser, 3... First hot well, 5゜6... Condensate purification device, 9...
・Second hot well, 11... Condensate reservoir, 1
2...Balance tube.

Claims (1)

[Claims] 1 It has a first and second hot well divided at the inner bottom of the condenser, and the condensate stored in the first hot well is sent to the second hot well through a condensate purification device. In the condensate device, a condensate reservoir is provided in the path leading from the condensate purification device to the second hot well, and the top of the condensate reservoir and the condenser are communicated with each other via a balance pipe. Condensing equipment.