JPH0440525B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for cleaning up a thermal power plant, and is particularly applicable to temperature control of condenser cooling water in a thermal power plant, a nuclear power plant, a marine plant, etc. Regarding.

The cleanup system of a conventional thermal power plant will be explained with reference to FIG.

In FIG. 1, 1 is a condenser, on the top of which a turbine 2 is installed, and on the side of the condenser a preboiler cleaning pipe 3, a steam separator drain pipe 4, etc. are installed. Further, a cooling water inlet pipe 6 connected to a circulation pump 5 is attached to the lower part of the condenser 1 via a cooling water inlet valve 7, and a cooling water outlet valve 10 is further connected to the cooling water chamber connecting pipe 8. The installed cooling water outlet pipe 9 is attached, and the other end reaches the discharge channel 11.

A conduit 12 is connected to the bottom of the condenser 1 via a condensate pump 13. 14 is a condensate desalination device whose inlet side is connected to the other end of the pipe 12; 15 is connected to the condensate desalination device 14 at one end via a low-pressure feed water heater 16; and the other end is connected to a deaerator 17. 18 is an auxiliary boiler (not shown)
A pipe line for supplying deaeration steam to the deaerator 17 from a steam source such as, 19 is a deaerator water tank, and 20 is one end connected to the lower part of the deaerator water tank 19 via a water supply booster pump 21. This is a conduit.

Reference numeral 22 denotes a conduit whose one end is connected to the outlet side of the water booster pump 21, a high-pressure feed water heater 23 is installed in the middle, and an outlet valve 24 of the high-pressure feed water heater 23 is installed at the other end. 22 is connected to a conduit 26 to a boiler 27, while also connected to the condenser 1 via a preboiler cleaning pipe 3 fitted with a valve 25.

Furthermore, the outlet pipe 28 of the boiler 27 is connected to a brackish water separator 29 fitted with a line 30 to the superheater;
A brackish water separator drain pipe 4 is installed at the bottom of the brackish water separator 29.
is connected to the condenser 1 via a valve 31.

To explain the conventional cleanup method for the low pressure preboiler system, high pressure preboiler system, and boiler system of a thermal power plant in the above configuration,
Pure water is purified by flowing it through the condenser 1, the pipe line 12, and the pipe line 15, and then the low-pressure preboiler system of the low-pressure feed water heater 16 and the downstream pipe line 15, the deaerator 17, and the deaerator water tank 19. After that, cleanup of the high pressure preboiler system will be carried out in the following order.

First, water from the deaerator water tank 19 storing pure water sent from the low-pressure preboiler system is used to pump water into the pipes 20 and 22, the high-pressure feed water heater 23, and the preboiler cleaning pipe 3 using the water booster pump 21. After water flushing, the high pressure preboiler system is cleaned up while water is circulated through the low pressure preboiler system and the high pressure preboiler system.

Next, the pipe 26, the boiler 27, the pipe 28, the brackish water separator 29, and the brackish water separator drain pipe 4 are flushed using the clean water sent from the low-pressure preboiler system and the high-pressure preboiler system, and then the low-pressure preboiler Cleanup of the boiler system is performed while circulating water through the system, high-pressure preboiler system, and boiler system.

This circulating water is heated in a deaerator 17 by steam supplied from a steam source (not shown) via a pipe line 18, and is heated in a condenser 1 included in the circulation system by a circulation pump 5 and a cooling water inlet pipe 6. The cooling water is cooled by the cooling water sent from the cooling water outlet pipe 9.
The water is discharged from the water into the waterway 11. Further, the circulating water is purified by a condensate desalination device 14 provided in the conduit 12 on the outlet side of the condensate pump 13.

However, the conventional cleanup method described above has the following drawbacks.

(1) Clean-up of a thermal power plant is carried out to remove iron rust, scum, dust, and other foreign substances in the system to satisfy the boiler water quality conditions. Normally, clean-up involves reducing iron content. It has become a key part of the process. In order to quickly remove iron rust and prevent the elution of iron from equipment made of steel, it is advantageous to perform clean-up using high-temperature water; however, in conventional methods, the temperature of clean-up water is approximately 50°C. Therefore, in order to reach a temperature higher than this, it is necessary to take measures such as reducing the flow rate of clean-up water or stopping the clean-up system circulation and producing hot water in the deaerator water tank 19. This method has the disadvantage that the process becomes long because it cannot be heated up, and the installation of a large-capacity heating steam source for raising the temperature is expensive and difficult to implement.

(2) In the conventional clean-up method, the temperature of the clean-up water could only be heated to about 50°C. This is because the water is cooled by the condenser 1 in the up circulation system and the water temperature drops to room temperature. In addition, heating of clean-up water in the conventional method must be done while circulating the water in the above-mentioned circulation system including the condenser 1, but in this case, the heated hot water is cooled to a temperature close to that of the cooling water. Therefore, excessive cooling is not desirable from the point of view of energy saving.

The present invention was proposed in view of the above-mentioned circumstances, and its purpose is to recover and utilize the waste heat of clean-up water carried away by cooling water to eliminate the above-mentioned drawbacks. The present invention provides a method for cleaning up thermal power plants that can be carried out effectively and in a short period of time.

The method for cleaning up a thermal power plant according to the present invention includes installing a cooling water bypass pipe in the condenser cooling water pipe of the thermal power plant, installing a valve for regulating the amount of cooling water in the cooling water bypass pipe, and The temperature of the clean-up water at the outlet of the condenser is increased by controlling the valve for regulating the amount of cooling water based on the signal of the temperature of the clean-up water detected from the pipe, and controlling the flow rate of the cooling water bypassed to the cooling water bypass pipe. The feature is that the clean-up water temperature at the outlet of the condenser is controlled by adjusting the amount of cooling water of the condenser cooling water in cooling the clean-up heated water circulated to the condenser. Prevents excessive cooling and increases the clean-up water temperature at the condenser outlet from the conventional 10 to 25℃.
It is designed to maintain a high temperature of around 55°C for effective cleanup.

An embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a schematic diagram showing the configuration of an embodiment of an apparatus used to carry out the method of the present invention.

In Fig. 2, 32 is a cooling water bypass pipe, 33
is a valve for adjusting the amount of cooling water (clean-up water temperature control valve). The valve 33 is controlled by a signal of the clean-up water temperature detected from the condenser 1 outlet pipe line 12, and the temperature of the clean-up water at the condenser 1 outlet matches the operating temperature of the condensate desalination device 14. Circulation pump 5 to maintain the appropriate temperature
The cooling water from the cooling water bypass pipe 32 is bypassed. The rest of the structure is the same as that shown in FIG. 1, so the same parts will be described with the same reference numerals.

In FIG. 2, the condenser 1 is short-circuited to the cooling water inlet pipe 6 on the upstream side of the cooling water inlet valve 7 on the discharge side of the circulation pump 5 and the cooling water outlet pipe 9 on the downstream side of the cooling water outlet valve 10. A formed cooling water bypass pipe 32 is provided, and a clean-up water temperature control valve 33 is attached to this pipe.

The operation of the above embodiment of the present invention will be explained.

In the above configuration, the cooling water discharged by the circulation pump 5 is sent from the cooling water inlet pipe 6 to the condenser 1, passes through the cooling water chamber connection pipe 8 and the condenser 1, and is sent to the cooling water outlet pipe 9 for discharge. It is discharged into waterway 11. On the other hand, the temperature of the clean-up water in the pipe line 12 at the outlet of the condenser 1 is detected at the same time, and based on the signal from this detection section, the clean-up water temperature control valve 33 attached to the cooling water bypass pipe 32 controls the cooling water from the circulation pump 5. By controlling the flow rate bypassed to the cooling water bypass pipe 32, the temperature of the cleanup water at the outlet of the condenser 1 is controlled to an appropriate temperature.

By doing this, the waste heat of the clean-up water after system circulation is used for the clean-up water at the outlet of the condenser 1, and the temperature of the clean-up water at the outlet of the condenser 1 is changed to the operating temperature of the condensate desalination device 14. Even if such factors are taken into consideration, the temperature can be raised to about 55℃. In the above case, it is of course possible to recover heat even if the water temperature after circulation returned to the condenser 1 is steam having a temperature of 100° C. or higher.

This heated water is sent to the deaerator 17 and heated with steam supplied from the pipe line 18 in the conventional manner to clean up the high pressure preboiler system and boiler system.

As described above, the method of the present invention provides the following excellent effects.

(1) By recovering and using the heat carried away by the cooling water in the condenser 1, it becomes possible to raise the temperature in the deaerator 17 by that amount, so the temperature of the clean-up circulating water is lower than the conventional temperature of about 50℃. The temperature is raised from 80 to 95 degrees Celsius to effectively perform clean-up and shorten the clean-up period by 30 to 50%.

(2) By shortening the clean-up process by recovering and using heat, the amount of heating steam is saved, making it possible to save energy.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a conventional example, and FIG. 2 is a schematic diagram showing the configuration of an embodiment of an apparatus used to carry out the method of the present invention. 1... Condenser, 2... Turbine, 32... Cooling water bypass pipe, 33... Valve for adjusting the amount of cooling water.

Claims (1)

[Claims] 1. A cooling water bypass pipe is installed in the condenser cooling water pipe of a thermal power plant, and a valve for regulating the amount of cooling water is installed in the cooling water bypass pipe, and the cleanup water temperature detected from the condenser outlet pipe is According to the signal, the valve for adjusting the amount of cooling water is controlled, and the flow rate of the cooling water bypassed to the cooling water bypass pipe is controlled, thereby maintaining the temperature of the cleanup water at the condenser outlet high to perform cleanup. A method for cleaning up a thermal power plant characterized by the following.